Family

I think your daughter is being ridiculous, frankly.
She won't stay in your house because your sister has been in it at some point?!

Assume your daughter sees this as a lack of loyalty on your part as by continuing to see her sister you are not supporting her. Not saying that’s right, but If they don’t want to sort things out you are left in an awkward situation. Can you just knock their heads together in a metaphorical sort of way?
I have a friend in a Similar situation with her 2 adult children. It is very sad. Been going on now for 15 years. With no contact between the siblings.
Hope things improve.

Heavens above, your daughter needs to grow up. Why on earth should you cut ties with your sister because your daughter says so? This is a problem between them and nothing to do with you at all! She really needs to understand that.

I meant your sister Annie. Typo.

I also think that your Daughter is being ridiculous but all you can do, is talk to her about it.
Of course, you're not going to fall out with your Sister because your Daughter had a disagreement with her but if you can't make her see sense, there's not much that you can do.
Who does your Daughter stay with when she visits then?
Where do you see her? Can you perhaps take the Grandchildren to see her, if it means so much to you?

For goodness sake, life is too short to be so petty. I can maybe understand your daughter not visiting at the same as your sister annie1948 but not to stay at all is beyond ridiculous. Are you sure there is nothing else going on you are not aware of.?
If there is no other reason I think you need to have a 'full and frank' conversation with your daughter.

Thank you all for your comments, very
Much appreciated

Without knowing more about the fall out it’s impossible to say whether Dd is justified. Would it be reasonable for her to worry about your sister popping in while she was visiting? Are your sister and DD normally the type to abuse alcohol?

This sounds complicated by the fact that both of them were "in the wrong" according to you. Have you spoken to your sister about it or is she oblivious to your situation?

Although it seems like your daughter is going a bit far with this, I for one have been involved with family disagreements that for some reason get out of hand and fester on for years. Logic goes out of the window. Could you guarantee to your daughter that your sister wont visit whilst she is there, and then if your daughter does stay it will give you time to try and get her to see your perspective. After all if you take sides it will guarantee that the rift will be for ever, and then you - and probably everyone else - will be the worse off in the long run. Easy to say I know.

Just meet up 'elsewhere' - simpler for you not to have house guests.

Buffybee
I think the OP meant that her DD won't stay at her house with her (the daughter's) children who are the OP's GC.

It feels like there's more to this. I wonder if, in the past, she's felt that you took someone-else's side and not hers? What's going on elsewhere in her life? How did they get on before this incident? Has anyone spoken to your sister about the situation? Can you not plead with both of them to work it out - maybe a "sorry" letter from each? (If not for their sakes, then for yours - stuck between the two of them). I've seen these family fallouts fester for decades if not tackled early on. Don't let that happen. Be proactive in getting them both to grow up and make peace.

Ahhh! Thanks for that Gabriella!
Got the wrong end of the stick there and making it more confusing than it already is. ?

that is so sad, but we have had similar. I've found that both time & listening to each point of view helps plus offering some sort of olive branch, maybe pointing out to each that the other was wrong but maybe time to let bygones be bygones? We're all here for just a very short time after all and it would be awful if anything were to happen to either of them whilst the feud festers. Maybe you could offer to take them both out to lunch somewhere else would help? I've often found towards the end of a few words about making peace getting both in the same room helps.

I’m on the side of those who say your relationship with your daughter is more important.

Hold her upside down and shake some commonsense into her!

I agree with OutsideDave. There is not enough information to know the circumstances.
Did you hear the whole argument, particularly how it started? Was anything particularly hurtful said? Did your daughter try to tell you why she was so upset and did you listen? What was their relationship like before?
You may have decided that they were both as bad as each other but your daughter has been hurt by something said and your sister has not.
You have dismissed your daughter's feelings by just deciding that it was 6 and half a dozen. Maybe it is but you are her mother and she should be able to talk to you. Tell you that you understand that she was hurt and will listen to her if she wants to talk. If she does, genuinely listen without any preconceptions. Acknowledge the things that your sister said that were wrong but explain that you are not able to cut her out of your life.
As long as your daughter feels that you have taken sides and you do nothing to correct that, you have to accept that the relationship will remain as it is.

I would just continue inviting both of them as and when I saw fit, and leave them to sort out THEIR issues.

How sad that a disagreement between your daughter and your sister leaves YOU as ‘referee’. They’re the ones who should sort it out, and I think you should say to each of them that it’s not your problem and you will welcome them both into your home - they should then decide what to do.

if your daughter wants to pay stay somewhere instead of accepting your invitation it's up to her. Tell her she can stay wherever she likes but you're not cutting off your other family and neither are you having an exorcism any time soon

You probably think that saying there was fault on both sides is you remaining neutral and not taking sides. No one involved will think this. More likely both will be angry you have ascribed blame to them.

Presumably you still have relationships with your sister, daughter and grandchildren? If so what are you currently missing out on? Are you able to enjoy visits with your daughter and GCs without having to clear up after them etc?

Families are strange, aren't they. My sister reported my daughter to Social Services after they had a row and it has certainly damaged the whole family. I wholly took my daughter's side and told my sister I would be civil to her at family events but that was as far I was prepared to go. My boys took the same line even though we had said we would not hold it against them if they felt it wasn't their row. I felt I absolutely had to take my daughter's side especially as my sister had always ranted on about how she felt that our Mum had never backed us. Certain members of my family were absolutely horrible about it but I just shrugged it off. They can forgive her, that is their prerogative. My daughter made it quite clear that she would not hold it against anybody who felt they couldn't take sides.
Whatever you decide is the way forward, that is the right thing to do. If your sister is the empathetic type, I might ask if she could apologise just so you don't get caught up in the row. I think healing the problem is better than taking sides if you can.

1. The relationship (or lack thereof) between two adults is not your problem to referee.

2. Your daughter isn't obligated to stay with you.

3. When your daughter is visiting, I'd suggest not having your sister over. And vice versa.

Perhaps the two of them need to realise and appreciate the damage they are doing to the whole family with their selfish attitude. One day one or the other will die and, in the grand scheme, a petty disagreement will never be resolved for any of the family