Are there any packages or custom solutions to allow an umbraco back office user to only manage members of a specific member group?  I looked and didn't find anything but wanted to make sure before going the custom route.

The requirement is this: 
We host several sites from Umbraco and need to have specific member only areas for each site.  Each site will have its own member group associated with their member only area.  We need to allow the customer to manage members only in their member group (and not have visibility to members in other groups).

Thanks