This is very similar to what I'm doing in a sitcom project I've been commissioned to write for. Only, with this one, there's only about three writers and a script editor.
The outline has already been (loosely) planned. Each writer will pick a certain scene to write. It's structured a little like League Of Gents with different characers heading down interveaving plots, so it won't be such a nightmare as, say, a sitcom with one main and one sub plot.
It will then be put together, then we'll all fill in the gaps.
However, I'd listen to Lee and Micheal if I were you, re both messiness of too many writers and the legal/rghts side of things.
Fewer writers and signed contracts would iron out those problems.