I recently started locking one cat in the bathroom when we're not around because he pees everywhere. This is an ongoing battle...part behavioral/part UTI issue. He is also a stressed out little freak of a cat. He seems to be doing much better with seclusion. More calm, uses the litter box, his coat even feels better. Go figure. Well, now the other cats hiss at him when I let him out into the house. Sometimes they even go so far as to swat at him. They all got along just fine before I started this. Any thoughts?