add simple workflow approval to grouper

Based on Vivek Sachdeva's work at UCLA, there could be some attributes on groups (or stems?) to setup workflow. These attributes identify the groups as workflow groups, and identify a group who has to approve the memberships. When a member is added (another API method?) then an attribute is added storing who added them and who was requested to be added. The group who approves get an email about it. They can login to the UI and approve the memberships or disapprove. That will remove the request. They could also view their pending requests. Would having a simple workflow be useful or would people need a more complex solution?