Membership management by email or web service?

Is there a way to send mailman administrative commands via email?

Or optionally, an API or web-service that I can use to communicate to a mailman instance about administrative changes?

For instance, we have a very dynamic list that may need multiple membership updates per day, which is not practical for the person who owns the list. Additionally, the list is private so it's not practical to simply open it up to unmoderated subscriptions. The membership is driven purely by another automated system (in this case, it is the instructor and staff hiring workflows for a department at a university), and the output of that process could be used to drive memberships automatically if there were a way to connect the systems.

The mailman instance that we use is administered by another group, so we don't have direct access to the database.

I poked around in the code for version 2, but I didn't find any mail-based commands that call ApprovedAddMember aside from AddMember. Am I missing something? Is there another way to issue administrative/membership management commands, either over email or via another automatable interface?

Thanks!