litterbox issues

Question
I have had two male declawed fixed cats (two brothers)Treye and Puck for 4 years now. I got them at age 2. I have had nothing but issue after issue with them peeing where they shouldn't, pooping where they shouldn't etc. I have tried all of the advice that my vet and other folks have given and about 25% of it worked.
They were peeing,(and still will if they had opportunity,) on throw rugs and anything hanging near the floor and on patches of carpet and boxes....even the front door when I really limited their options. When it got warm I enclosed the back porch and started ptting them out there so that if they did pee, it would be at least somewhere cleanable. BTW, I live in the hills of the city here in Pittsburgh.
 It got worse then virtually stopped dependent on the outside cat traffic.
 Treye just had an infection, and went on antibiotics. They gave him the runs and so he started pooping outside the box. THEY HAVE THREE CLEAN BOXES TO CHOOSE FROM AND ITS THE ONLY LITTER THEY LIKE.
After he felt better he opted to just,well, keep doing it that way. He pees in the boxes, just not poop. I'm currently keeping him locked in a room with a litterbox to try and retrain him.
Absolutely no one has offered any advice on what to do. I want to get them new collars and let them go outside and get the outdoor obsession out of their bones. That will probably not work I'm sure and they're declawed blah blah blah.....I know treye would be happier outside though...
I am simply out of ideas, sick of cleaning and almost out of patience. I told them its only their cuteness thats keeping them from the humane shelter (it's no-kill). Ah yes and the catch: When I separate them, they miss each other and get really sad and cry--even though they fight on occasion voraciously.
The shelter said they can't guarantee they will get adopted together...
I am at my wits end. Any advice?
Thanks.

Answer
Hi there!  This is a tough situation.  It doesn't sound as though the boycotting of the litter boxes is coming from a health problem, but more of a behavioral problem.  I know you have probably already been told this, but what if you would put them in a room with all three litter boxes...and each week, keep increasing their space?  Sometimes, I have heard that this works.  Other than that, the only other suggestion I have is to talk to your veterinarian about recommending an animal behavioralist.  Animal behavioralists range in price from resonable to absolutely bank breaking, but they have been known to help with situations like these.  I wish you all the best luck and I wish so much I had better advice for you.  Please let me know how it goes and I hope things work out for the best.
Hilary