My partner and I moved in with his sister last summer. We have two cats (both female, spayed & three years old) who get along really well. She has two cats (one male, one female both neutered/spayed and about 4 years old) who tolerate each other. But they both really dislike our two cats. Hers mostly stay upstairs and ours mostly stay downstairs. Her two like to corner and start fights with one of ours every time they’re downstairs and she’ll barely fight back but does hiss at them and avoids them at all costs now. Within a few weeks of moving in together I started to smell the piss in specific corners where the bullied cat likes to hang out. We’ve done everything I can think of to help. We got calming collars for all four cats, calming pheromone wall plugins, an extra litter box literally right where the markings are happening, spraying with enzymes and cleaning the carpets as much as possible. Nothing is working. The bullying isn’t every day, the cat fights have died down in general, and all 4 cats have calmed down with only a few spats here and there but the stench of piss remains. Every time I carpet clean it smells better for a little bit but then it comes back, I’m assuming because the bullied cat is marking her territory.

What other solutions are out there?? Moving is not an option at this point. Am I just stuck with the smell until we can move?

Pic of my two girls.