Some of the major challenges in group dynamics are the speed, pace, and focus of the individuals and group. This is why facilitated sessions are so valuable as they get people focused and paced similarly.  For us at IN8 Create, we love using LEGO Serious Play as our primary method. Like Reese's Pieces, It breaks down the session into bite sized rewarding segments.  I purposely use the term rewarding because for each challenge question, participants get to create a LEGO model and a story that's tied to it.