I have 2 kitties that are 7 months and I acquired another cat, seems full grown, is a big one. They are all girls, and my 2 kitties hate her. They always try to claw and hiss when she is near. They are all girl kitties. She is real nice and doen't hate my kitties, and she doesn't even try to fight them. Anyone know how I can get my 2 kitties to like her?