I want to allow the administrator and manager roles to be able to create groups (for example different jobs within a company) and be able to assign users to the groups. I want this to be a one-to-many relationship so that user1 can be assigned to job1 and job2 (or no job) but user1 can't be assigned twice to the same job.
How would I go about starting this or what is a good module and/or resource to utilize?