The downstairs was changed into a group rental house, which was particularly disturbing to the people. The property company did not stop it, and it did not work. Can I sue the property company?

It's no use suing the property company, which they don't want to see. Moreover, the litigation cost is very high, which is not binding on the owners of those rented houses. You might as well sue the owner directly. Or 1 10 calling the police is better than suing the property.

It is illegal to rent a house in groups now. If you want to call the police, the police must intervene.