Good guidelines for starting a writers' group (at Script)

Chad Gervich over at Script has a good post today with some guidelines for starting a writer's group.  He's talking about a group for screenwriters, but I think his ideas apply whether your making a group for screenwriters, playwrights, or novelists.  (I've been in groups for plays and novels, but have never found the right one for screenwriting.)  I completely agree with his basic guidelines--for a group to work you need: writers of a similar creative/skill level, who share basic professional goals, and who are strongly committed to the group.  And most of, you need personal chemistry--if you don't like each other, the group won't last.