codice:
Sub stampa()

Dim tot, i As Integer
tot = ActiveDocument.BuiltInDocumentProperties("Number of Pages")
For i = 1 To tot Step 3
  pagg = pagg & i & ","
Next i
pagg = Mid(pagg, 1, Len(pagg) - 1)
Application.PrintOut FileName:="", Range:=wdPrintRangeOfPages, Item:= _
        wdPrintDocumentContent, Copies:=1, Pages:=pagg, PageType:= _
        wdPrintAllPages, ManualDuplexPrint:=False, Collate:=False, Background:= _
        True, PrintToFile:=False, PrintZoomColumn:=0, PrintZoomRow:=0, _
        PrintZoomPaperWidth:=0, PrintZoomPaperHeight:=0
End Sub
Hai ragione, scusami.
Vedi se così va.