The final price is determined by supply versus demand, not by the number of subrenters in chain. The real problem in your situation is that these people are ab

The final price is determined by supply versus demand, not by the number of subrenters in chain. The real problem in your situation is that these people are able to rent flats for sub-market prices. But it's not your problem. Your problem is that you don't have enough realty supply. And/or more people who want to live in interesting city than interesting cities of Switzerland can house. The latter seems to become a major problem in most countries.