Planning session advice

I am a relatively new planner in the field (received my Master's in 2008) working in community revitalization and planning. I am doing research on planning charrettes and design sessions that have successfully brought together opposing groups or that have been successful in potentially hostile environments, where community members have conflicting ideas about community identity.

Specifically I am looking for examples of best practices on how to conduct such sessions to maximize participation in a culturally diverse community and to minimize disruptive conflict between community members.

I would appreciate any specific detailed examples, advice on how to conduct them, or ideas about groups that have had success in similar situations. Thanks!