I am heartbroken for you. Our elder DD and her DH have always included both sets of parents since the day they were married, and similarly since the GC came along. The other GPs do see more of them cos they live within walking distance and we are 30 miles away, but overall they do their best to share things with us all. Fortunately we get along well with the other GPs (so long as we don't mention politics cos ours are quite different from theirs!) and want to keep it that way.
You never know, as the GC get older you might find you have a closer bond with one or both of them, or a different bond depending on their hobbies, so you can make the most of that.
As others have said, keep stum as far as you can cos it seems it can soon go pear-shaped and I can tell that you wouldn't want that