Zugriffsberechtigung je nach Benutzernamen

Private Sub Workbook_Open()
Dim wks As Worksheet
Dim strName() As String
Dim lngIndex As Long
Application.ScreenUpdating = False
Select Case UCase(Environ("Username"))
Case "USER1"
ReDim strName(0)
strName(0) = "a"
Case "USER2"
ReDim strName(5)
strName(0) = "a"
strName(1) = "b"
strName(2) = "c"
strName(3) = "d"
strName(4) = "e"
strName(5) = "f"
Case "USER3"
ReDim strName(2)
strName(0) = "x"
strName(1) = "y"
strName(2) = "z"
Case Else
Exit Sub
End Select
ThisWorkbook.Worksheets(strName(0)).Visible = xlSheetVisible
For Each wks In ThisWorkbook.Worksheets
If wks.Name  strName(0) Then wks.Visible = xlSheetVeryHidden
Next
For lngIndex = 1 To UBound(strName)
ThisWorkbook.Worksheets(strName(lngIndex)).Visible = xlSheetVisible
Next
Application.ScreenUpdating = True
End Sub