I am in danger of losing one or two of my precious boys (cats). I have 6 cats in the house.

I love all of them very much. Each one is either a stray, rescue, or one I have adopted from an
animal shelter.
I have 2 male cats (neutered when they were very young) that have a "spray" war going on. They don't like each other, and never have, so they try to saturate the house with their spray to see who is the boss, I guess. My mother lives with me, and is sick and tired of our house smelling like cat pee. It's really bad. They completely ruined a couch, a chair, and big patches of carpet, walls where paint has come off, and our kitchen cabinet doors are warped because of all the "urine." She wants me to get rid of both or at least one of these cats. I just can't bear to do it. These 2 males are the most affectionate to me, and they just love me. One of them has cerebellar hypoplasia, and I can't just put him anywhere. He is very dependent on me.
My mom keeps thinking that there is some kind of a hormone pill or something that might make them stop doing that. Do you know of anything like that? We have tried Feliway, but the areas are so bad that we can't get the smell out before we put the Feliway there, so it doesn't work. Also, the Feliway is so expensive...
Help!! I don't want to lose my boys!