How to Edit User Account Group Membership in Lion Server
After you create user accounts in lion Server, you can assign them to groups and those group assignments can be changed as needed. With Lion Server’s Workgroup Manager Users (head icon) tab selected on the left, you can set group membership for the selected user in the Groups tab on the right. Near the top are fields for primary group ID and short name.
By default, all new users created in Workgroup Manager are members of the primary group called Open Directory users, which has a short name of staff and a group ID (GID) of 20.
When you click the Add (+) button, a Users and Groups drawer slides out of the Workgroup Manager window. Change the primary group by dragging a group from the slide-out list over one of the three fields — Primary Group ID, Short Name, or Name.
Additional group membership can be added by dragging groups to the Other Groups list.
Because groups can be members of other groups (called nested groups), click the Show Inherited Groups button to see additional groups that the user is a member of via nested groups.