Wow a lot of MD people on this site!
I tried to tell my big girl that she used to be the new, tiny kitty one time too and she needed to give him a chance. He didn't understand why she was so mean to him. She quickly smacked me on both sides of my face and told me in no uncertain terms that she didn't want to hear that. Well, they snuggle now and they groom each other but when they are done they hiss and they leave each other alone. I never had blood or vet bills. They will work it out for themselves. I know you want to try to make everything right for them but remember they are animals. Thats why you have the opposable thumbs, to do the quilting.lol