Elda...You may have no choice but to call Animal Control!
You can use predator urine like fox or coyote to repel the cats.
They normally don't pee where they eat, so someone around must be feeding them and they find your patio a good litter box. I have never had feral cat problems in our yard, but have had to take care of odorous cat pee problems in the house. I spray everywhere that smells like cat pee with full strength vinegar and it removes the odor. I can easily take more than one try, it is not easy to get all the areas the first time around. Perhaps if you can rid the area of the odor they will quit using your patio as a litter box. Once the odor is gone, you can use one of the suggestions to keep them away.
First, clean up the smelly area with a hose and scrub with ammonia and long-handled stiff brush. Rinse and let dry. Liberally sprinkle dried red hot pepper flakes, cayenne pepper and moth balls from the from the Dollar Tree. The cats won’t like the cayenne and flakes on their feet, and their tongues will burn temporarily when they lick their paws. Do this until they leave your area. Hen put out pots of plants that cats don’t like to keep them away.
I have people walking their dogs and they stop and urinate on my plants so I use a product called Liquid Fence dog and cat repellent and it is harmless to plants and animals. I just spray around where they have been urinating and it stops them from that area. You can apply it to landscape beds,trees, and other areas where pets and or strays are not wanted in that area for there urinating place. It can help your pets and other strays learn the correct behaviors. It has worked for me.