Keep your daughter's cat in her room to start with, or if it is possible in two ajoining rooms.
Your cats will become curious and after a while you can let the newcomer join the two others.
They will probably hiss and spit at each other. If possible, leave them to sort things out for themselves, but obviously you will have to intervene if a serious fight or bullying is the order of the day.
It is a good thing that your daugher's cat is younger than yours, as usually a young cat will defer to an older one, irrespective of sex.
Scottish political mess. Is Devolution working?