try showing the cat that doesn't get along, extra attention. She or he may be feeling unloved, or inferior. Tender loving care may be the answer, or just accept. We don't like some people so maybe she does not like some cats. meow

well I have had trouble with my cats in the same way, first of all you must conseder that your cat mite fell a little lift out so try to spend more time with her and not so much time with the others. try bying special treats for her and try liting her sleep with you show her that you still love her very much.