I have 3 cats, and used to have 5. Are these cats fixed? If not, you're pretty much screwed and they're going to spray all over the place no matter what. If they've been pissing everywhere for a long time it will be extremely hard to break that habit as well. Here's how I'd try however.
Is the cat litter dirty? Change the cat litter often. Sometimes cats will piss on things because their cat boxes are too dirty.
After ensuring you have clean litter, go to a pet store and buy something to eliminate cat piss odor and apply it to the worst places you can find. If a spot smells like piss already, often a cat will piss there again and again. If it doesn't smell, sometimes they'll stop.
One caveat to my advice: it hasn't worked for me. One of my cats pisses on things in our house. We've tried everything short of electrocuting his nads to get him to stop. If he's mad at you he'll piss on you while you sleep. Now THAT is something to get angry about. We just throw him in the shower and turn on the water and spray him when that happens. Is it a deterrent? Who knows, but it's satisfying to watch him squirm and has perhaps help prevent me from strangling the life out of him. He's 16 years old and we're holding off on things like buying new furniture etc... until he passes on
