'Add a group to a user
Public Sub AddGroup2User(strUser As String, _
        strGroup As String)
    Dim wrk As DAO.Workspace
    Dim usr As DAO.User
    Dim grp As DAO.Group

    Set wrk = DBEngine(0)
    On Error Resume Next

    'Create object references
    Set usr = wrk.Users(strUser)
    Set grp = usr.CreateGroup(strGroup)

    'Add the group to the user's Groups collection
    usr.Groups.Append grp
    usr.Groups.Refresh

    Set usr = Nothing
    Set grp = Nothing
    Set wrk = Nothing
End Sub