Ive used feliway... Its a replica of the happy cat pheromone. I have a kitty who pees on my bed every time we bring a new cat in to the home (we rescue cats and most times dont adopt them out once we get attached.) This spray makes her feel happy and not aggitated by the new arrivals.. it works pretty good.
Ive never found anything else to work. She has been with us 6 years or longer and she is fine until we bring in a new kitty then for days she will pee. Once she gets some feliway sprayed around her she gets contented. Mind you we have to give her tons of rubbings and pettings ( more than usual) so she knows we still love her. They are like kids I tell you.
Good luck with your pee kitties
If you need a good product to get the stink out there is a locker room deoderant called Knock out. used in gym bags. It takes the stink outta anything.. even works on eliminating the odor of male spray ( which we had to deal with this week with out latest arrival who is at the hospital right now getting snipped OUCH!)


How long have these kitties been living in the same home? Maybe its a time thing.. I currently have 14 in the home and with in weeks  ( some times months for some) they all tend to get along. They eat, sleep an play together usually.