How to restrict VBA to Named Range?

I have this code, and want to restrict it two 2 named ranges instead of the entire worksheet. What is best way to do this. Not very familiar with VBA.



Private Sub Workbook_SheetBeforeDoubleClick(ByVal Sh As Object, ByVal Target As Range, Cancel As Boolean)

ActiveCell.Value = Now()

Application.SendKeys "^{return}"


Target = Format(Time, "h:mm:ss")

Cancel = True


End Sub