I have 3 male orange tabbys, all brothers. 2 of them are really friendly to anyone that comes into my house. The third cat however does not do well. I live alone and he is a sweet heart to me, super clingy and affectionate. But once anyone comes in my house he approaches them and will rub up on them, pretend to be friendly and attack. He hisses and strikes at them, goes away and comes back then tries to attack again. I don't know what to do and I hate to lock him up anytime someone comes over.