Well, I think they would use the same loo, when I had two cats they both used the same litter box. It may even be easier if one cat is trained, a kitten may learn by example? The goal is to eventually have no ring and they just hop up and do their business. I have heard you can teach them to flush, but I do not think that is a good idea. I think my little monster would flush for fun, she loves to watch the water and stick her paws in if she can.