Hi Debra!
Your observation of group challenges are right on target. A few other challenges that I have experienced is placing people in groups, having the antagonist in a group, people who are no shows for the presentation portion, and the "know it all" just to mention a few.
But the good thing that I have learned that approaching students and having a reasonable conversation has been mostly successful for working these challenges through.
Keep up the good work!
Jane Davis
ED106 Facilitator