Unfortunately, Airbnb will see these guests as completely separate to the first guest. Have you cancelled the rest of the original guest's stay? I would call Airbnb to cancel on them as they have broken your rules. That might be enough to drive their friends away. If not, call the company again at the first sign of rule breaking rather than wait and keep having to talk to them.
I forgot to mention. If you call the company, and if the guests have broken rules, you will not be penalized (the company will do the cancelling in this case).