Just want to add one thing, you have the advantage coming in to your position. When you address this issue -and it needs to be in the first meeting and early in your opening remarks- introduce it as a topic you've been asked to address (you asked yourself to deal with this right?). Also an additional concern I would think would be your group developing a reputation of being a rude group speakers would want to avoid. As a teacher I agree with having the group involved in the solution- this is more effective with any age group then being told this is what will happen. Owning the solutions makes compliance a greater possibility.