Managers can edit Custom Member Groups by clicking the Edit button on the Customization bar. The Edit Group window will appear in which a Manager can make changes to the Name and Description of the Custom Group. The window will also show whether the group is Private or Shared, and instruct you to save your changes as a new group if you want the group only visible to you.
You can also delete the group by clicking Delete this Group. The Delete Group window will confirm that you want the group deleted with a reminder that the group will also be permanently deleted for the other Managers who have access to it.