In the Groups menu of the Site administration you can:
The first page you see when you click on the Groups menu is the Administer Groups page.
You can add to or remove administrators from a group by clicking on the Manage button on the Administer Groups page.
Add or remove group administrators
Group categories help you to filter your groups more easily on the My groups and Find groups pages. A group administrator can always assign one group category to a group if categories are enabled.
Site administrators can manage group categories on the Group Categories page under Groups in the Site Administration.
Manage group categories
Note
Group categories are not hierarchical and are available to everybody on the site. Any user who can create groups can assign a group category.