Couple of options (if you cont. having to live "with" the cats).
Mothballs, cats hate em. Now, how you arrange them is another matter but crushed mothballs should make a feline take a wide birth.
If, on the other hand, getting them to favour 1 particular place is a better alternative, try hiding some catnip in an area. This should illicit feline addiction/interest in one spot.
Also, have heard (and this could be a tricky/messy one) that going to the local Zoo and talking to a friendly keeper might help. Yeah I know, sounds strange (and I am not volunteering lol, not got cat problem luckily anyway) but a small amount of "predator" urine is apparently a sure fire way to strike the fear of god into a feline!
Now how this would help with laundry (hmm, replace cat piss with tiger piss, good swap LOL) I have no idea, but interesting idea and great pub conversation lol.
"Hey what you get up to today?", "oh I went to the Zoo to collect Cougar piss" ROFLMAO