Bulk Group Permission Change Tool
Group memberships can be handled in large quantities using the bulk change tool, which can be found at the bottom of the Custom Space User Management Plugin settings page:
(Browse or Space Tools) > Manage Users/Groups.
Group permissions can be edited by the same means used to edit user permissions (Space Tools > Permissions or Browse > Space Admin > Permissions) or from the Plugin settings page ((Browse or Space Tools) > Manage Users/Groups > Edit Space Permissions). Both links lead to the same place. Groups that you have permission to edit will appear at the top of the page under the Groups section.