Here is the setting: We have a neutered male siamese Mickey, 11 years old, that we adopted. He is an inside cat but we put him on a leash and walk him like a dog when the weather is nice. We rescued Leeloo, a 2 year old female siamese mix and had her spayed, she and Mickey took a while to live together but now they're pals. Lilly is 4 year old outside female cat that we started feeding last winter and we bought her a heated cat tube that sits on our front porch. Lilly and Leeloo "scrap" through the patio glass door. When the weather is very cold we bring Lilly in from the outdoors and put her in my son's upstairs room with food, water and her own litter box. We are hoping that Lilly can someday become our third indoor cat, but for right now Lilly is not allowed to mingle with Mickey and Leeloo.
Mickey occasionally sprays coats and cabinets for the last several years even before Leeloo and Lilly were adopted. It's just Mickey and repeated attempts to try medications hasn't worked well. When the weather is warmer, he is allowed to go outside on the leash to spray the bushes, which appears to cut down on the indoor spraying. But in just the last month, Leeloo has started urinating on clothes and drop rugs. This can be anywhere in the house, not just where Mickey sprays. I don't know if this is behavior or UTI but I'm taking her to the vet next week. We have three litter boxes for Mickey and Leeloo, all kept very clean. And I know that Leeloo still urinates in the litter boxes. Food is wet canned food and bagged dry cereal.