Sally, it has been my experience with cats that getting a 3rd cat may not alleviate the problem. I have a similiar problem with Mopsy and Otis. Otis is definitely the ruler of the property and in the house. He darts outside, when I am not looking, and runs off all of my strays, and ferals and then comes back when he has done his "work". Otis and Mopsy do not get along, because Mopsy will not accept him. Although I have seen both of them tolerate each other, Mopsy appears to be afraid of him. I know that they will not eat out of the same tray. Sometimes I hear the loudest cat fight cries, and assume that Mopsy is being chased by Otis, which is usually the case. I doubt that either will accept each other, but as long as they do not constantly fight, I can put up with it.

........wayne