Private Function ListUserGroups(ByVal U As String) As String
            Dim sList As String = ""
            Dim groups_List As XmlNode, gr_Members As XmlNode

            Dim WS_UG As New WS_UserGroup.UserGroup
            WS_UG.Credentials = System.Net.CredentialCache.DefaultCredentials
            groups_List = WS_UG.GetGroupCollectionFromSite()

            Dim iGroup As Integer, sGName As String, iUser As Integer
            Dim sLogCode As String
            Dim gr_Nav As XPathNavigator

            For iGroup = 0 To groups_List.ChildNodes.Item(0).ChildNodes.Count - 1
                gr_Nav = groups_List.ChildNodes.Item(0).ChildNodes.Item(iGroup).CreateNavigator
                sGName = gr_Nav.GetAttribute("Name", "")
                gr_Members = WS_UG.GetUserCollectionFromGroup(sGName)
                For iUser = 0 To gr_Members.ChildNodes.Item(0).ChildNodes.Count - 1
                    gr_Nav = gr_Members.ChildNodes.Item(0).ChildNodes.Item(iUser).CreateNavigator
                    sLogCode = gr_Nav.GetAttribute("LoginName", "")

                    If sLogCode.ToUpper = U.ToUpper Then
                        sList = sList & ";" & sGName
                        Exit For
                    End If
                Next

            Next
            If sList.Length > 0 Then sList = sList.Substring(2)

            Return sList
        End Function ' --- ListUserGroups