Please help
Hello everyone my family and I run a small sandwich shop and we have been spending thousands on a bathroom that keeps clogging. There is a main line about 5-6 feet from the bathroom door with a 4-5inch pipe and another line in the kitchen that is about 2inches. When I check the main line it is empty. Previously in the kitchen line it would be clogged with paper towels so we eliminated paper towels and went with an air dryer and hired a professional to snake and hydro Jet all the lines. A week later the bathroom was clogged again and the plumber came back and snaked all the pipes but it was the 2inch pipe in the kitchen that finally unclogged the toilet. A couple months have passed and it is doing it again. Is there a reason why the bathroom flush would come into the kitchen line when the main line is way closer. Also I am looking to buy a commercial snake to help with maintenance any suggestions would be nice. I would like an honest opinion on how to solve this we are already have been spending so much money for each time we call a plumber. I respect the the Plumbing community but it just seems it’s to frequent thank you to all who read this.