In the User Manager an administrator can change the usergroups that a user is a member of. The administrator can only make the user a member of the usergroups that the administrator controls (ie so that the administrator cannot promote a lesser user to leapfrog above the administrator).

Automatic membership

Automatic membership is a powerful control that allows you to provide different visitor experiences depending on what Domain the visitor is coming to, what IP address they are coming from or what Browser they are using - allowing automatic switching for mobile devices.