Yeh, it's a tough situation.  We can't be the teacher, but we can work with the teacher.  In effect, try to tell them what to do, though please don't hold me to putting it so bluntly.  Maybe we can get some of our senior people there at the right times to talk to them; Russ for instance carries some authority with teachers as a CPS veteran himself.  Meanwhile, I don't think you can wield authority with the students, but perhaps you can put it on a personal level ... they're making such a racket you can't concentrate to do your job, that sort of thing... What do you think?