XL 2010 Cherche comment faire un type macro

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
Dim a As Boolean, b As Boolean, c As Boolean
a = Not Intersect(Target, Range("A3:D1042")) Is Nothing
b = Not Intersect(Target, Range("E3:H1042")) Is Nothing
c = Not Intersect(Target, Range("I3:L1042")) Is Nothing
If Target.Row >= 3 Then
Application.Run "Macro" & (a * -1) + (b * -2) + (c * -3)
End If
End Sub

Sub Macro1()
MsgBox "Lancement Macro1"
End Sub
Sub Macro2()
MsgBox "Lancement Macro2"
End Sub
Sub Macro3()
MsgBox "Lancement Macro3"
End Sub

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
  If Not Intersect(Target, Range("A3:D1042")) Is Nothing Then Macro1
  If Not Intersect(Target, Range("E3:H1042")) Is Nothing Then Macro2
  If Not Intersect(Target, Range("I3:L1042")) Is Nothing Then Macro3
End Sub