I have a problem like that with Sasha (my roommates cat) and Corkscrew. And sadly poor sasha is declawed (she was like that when my roommate got her) so she can't defend herself. But I've learned there really isn't much I can do. Corkscrew is great with Tibby and was great with Zasper but he and Sasha don't get along. I think they both want to own the house. This is what everytime the two of them get near each other.