I'd second this...though I don't know that you'd need a plug-in...I've been doing something like it for years without (but then, I'm used to doing stuff the hard way, so...).
Create the cohort, add all your users (including supervisors). Create the groups in a csv spreadsheet (excel, column A row 1 called groupname. That's it...list all your group names in column A under the header, save as csv). Import the csv to each course. Cohort sync enroll to each course, adding to the group on cohort enrollment. I would then make sure to give your supervisors the extra (Supervisor) role they need. If someone changes teams, you change their cohort (put them in the new cohort first, then remove them from the old, you might check to remove them from the old groups, though).