I doubt many people here have enough exposure to poly tribes to comment. It seems you have a fairly large and close-knit (in terms of most people knowing each other) poly community where you are, RP, and I would think that is really out of most folks' experience unless they actively seek out the groups in their area.
That being said, I am sure there is usually at least one person in a poly tangle who takes on a leadership role, comes up with ideas about spending time, reminds others when to sit down and discuss issues, etc., but hopefully they allow for all involved to have a vote or say in what is happening, especially the more important stuff. A good leader knows when to be up front ahead of the pack and when to sit back and give others their turn.
I don't really "get" how it works for anyone in a poly tangle to have a potential love decided upon "by committee," however. That idea creeps me out.
The world opens up... when you do.
Oh, oh, can't you see? Love is the drug for me. ~Bryan Ferry
"Love is that condition in which another person's happiness is essential to your own." ~Robert Heinlein