HELP!! Kitty pee!!!

OK, I really need help here. I have 3 cats, one coon cat 5 years old that goes outside, and 2 Siamese siblings 1 1/2 years old that are house cats, but go out on halters. A month ago there was a neighborhood cat that peed in my basement window, which started a mess. We started seeing pee all over the tables, and counters, no furniture or carpet. Called the vet and did tests, both housecat's had infections, did rounds of antibiotic, put on Royal Canin urinary SO 33 vet food, water fountain, got clean urine!! Still…finding pee on hard high surfaces. Took the 2 Siamese to the vet, she said that the male was very sure of himself, not afraid of anything, hyper, and marking me like crazy. She felt that he was bulling his sister and she was getting up high to get away from him and peeing. SO…put litter boxes on all 3 floors of the house, separated them to try to figure out which one it was, and didn’t take long. First time we were gone there was pee all over the table when we got home, and the male was the one in the house, his sister was downstairs, and my Coon cat…he’s outside all the time, so it wasn’t him. Now we have him on Valium, 1 mg 2 tx a day. I hate doing the drugs, but he is so calm now, his sister comes around more and is playing with her mice again. I thought the reason she stopped playing with them was that she got bored with them. Started the valium on a Thursday night, all was good, Saturday, we went out and he peed again on the counter? NOW…I’m TRULY at a loss, and just don’t know what to do!! I can’t have him peeing all over my tables and counters, but I don’t want to lose him either. HELP!!!

Same places, kitchen counter, kitchen table. When this all started he also hit the dining room table and end table in the living room, that has stopped so I am assuming those were from the infection, however it has continued in the kitchen. Don't get me wrong, I am grateful that it's not the carpets, but would like to end it all!! I am thinking it's behavioral, or as I read somewhere it's because he has done it there, so going back. I am using the recipe that I found online to clean it, vinegar, baking soda, hydrogen peroxide and dawn dish soap. I don't smell it, but that doesn't mean that he doesn't. I also have a felaway that I place in the center of the house, I have a small house...but after reading here last night, I put it in an outlet over the counter? Not sure if that will help but will try anything. Thank you so much for responding, I am feeling like there is nobody that understands or can help me figure out how to correct this. Please tell me this is correctable!

It’s been a while, but I thing that we have it licked. My vet suggested that I put my cat on valium, I really was not for it, but was so totally at the end of my rope that I agreed. I also plugged in the feliway in the outlet on the counter. The peeing stopped instantly…which kinda freaked me out a bit, but was glad. I did cut the valium in half as the vet said I could, and giving it two times a day, after about 1 ½ - 2 weeks, I cut it down to 1 pill a day for a week, then stopped the meds. He has done GREAT, until we went away for the night to friends. We came back in the morning and there was pee on a different counter in the kitchen. At this point, I’m thinking that the initial messes were because he was triggered by the stay cat in the area. With us going away overnight, the three cats at home in the house; he got mad or upset that we were not here and did his thing? It’s been a couple of weeks since that morning, and he has not peed since. Could my thinking be right?