Please help

I recently moved 1300 miles with my 2 cats into a home with 2 cats & 2 dogs. My cats get along fine with the dogs but 1 of the other cats & my 2 do not.It started with simple hissing and fighting. It has now become pissing over each others spots and an occasional poop. We have tried everything from framon srpays to plug-ins.We even seperated them & it made no difference.As a last resort we are considering having 2 seperate homes so they will all be happy but us.Please help so it doesnt come to this.thank you.My cats cats are 10 and the other is 12.

Okay, it sounds as though the problem is mulit-layered.
   
I think this may be a turf problem, originating from the housemate's problem cat, but I need more information. I need answer to these questions before I launch into a theory:
   
Your cats: Sex of the 10 year old? Sex of the 12 year old?
   
Their cats: Sex of the problem cat & age?
   
Is everybody spayed?
   
Who started the hissing & fighting? The housemate's cat, or your cats?
   
Also provide names for the parties involved (your two, the housemate's cat), so the next posting can be less confusing.
   
In the interim, before we get this solved, it would be best alternate access to the common areas. Set up a schedule: trade off your two cats & the housemate's cat in the common areas, say by several hours at the time. This will probably require extra litter boxes, but that's a small price to pay for temporary peace.
   
Also totally deodorize the areas the cats have gone on. If it's all over several rooms of carpeting, call a carpet-cleaning service & contract for the Pet Odor Removal service (they all have it). Getting a couple of rooms professionally cleaned isn't expensive at all.
   
If it's hard floors, go to the pet store & buy the strongest odor-removal product you can & use it, with strong soap like Spic 'n Span, on the floors.
   
After you post again, I'll get into Cat Politics and Turf Wars, which I think is what's going on here.
   
I may not get back to you before Monday; I don't have time to websurf on weekends.

Thank you for responding. My cats are:Bubba who is male and Patches is female. Her cats are:Keyboo and Baby both female.They are all spayed. Keyboo stays to herself and has no problem with anyone.Baby on the other hand does not like my cats.Baby and Pathes were the dominant ones of there homes. They are also the ones having the most problems.Bubba is usually laid back but seems to get the brunt of the other two and has since gotten himself involved.I believe it was a joint effort on Baby and Patches part to start the fighting.Since than the 3 of them have all urinated on each others spots.Her cats box and food are in the garage and mine are in a spare room since they cant get along.Baby however will go into the room and eat there food.Baby and Bubba will lay next to each other one time and beat each other up the next.