I'm sorry to hear this. Have you tried Feliway spray or plugins? I've been using 3 plugin's since last summer when I was having peeing and aggressive issues. I also still sometimes use the spray. It's been helping a lot but they'll still have some fights. I also give a few of my cats some herbal calming pills that my holistic vet had recommended. My cats have to live together because there's really no way to separate them. Good luck.