RICO would very neatly fit this sort of circumstance I think, and each individual molotov cocktail should count as a predicate act, meaning that one afternoon should be enough to satisfy the predicate act requirement. The enterprise requirement is very broad, so it should be possible to scoop up many of them, even if they only tangentially know each other.
If professors/students are involved, the schools might be subject to being included in a RICO action as well, both criminal and civil.