We try to do everything as simple as possible on 573. Like many other teams, we have 5 subgroups: project management, chassis, appendage, electronics/programming, and promotions/communications.
As to how we grouped each of our 25 members, the student subgroup leaders and the mentors had a meeting in which we took the sheets that everyone filled out (which detailed personal talents AND interests). We grouped them according to these factors, making sure that the 5 subgroups were at least somewhat balanced quantitatively and experience-wise.
The mentors and the student leaders, while focusing on one subgroup, did float around to other subgroups to fortify communication lines within the team.
Every other week or so, the student subgroup leaders discussed any problems at hand (lack of resources, reevaluation of season agenda, etc.), and addressed these with the mentors.
We were lucky to have parents willing to organize all things concerning food for us.
Our overall organization method proved to be very successful for us during the season. It kept us on track, and made sure that each person had something to do.