Set a trap. Video record them and see if you recognize any of them. Then call the police and file a complaint. Just catch one or two, prosecute and see if that helps the problem after the word gets out.
yeah dude if you know their names and where they live and know for a fact that it is them then call the cops and have them talk to the little jerks. i think it would defiantly scare them into stopping that nonsense.
If you know who is doing it then I would suggest you talk to their parents first. If that doesn't stop it, call the police and file a report. I wouldn't suggest breaking their fingers. That is a lot worse of a crime.