Imbrication de deux procédures

bonjour à tous et bonne année 2008
j'ai un petit souci sur deux procédures que je n'arrive pas à dérouler l'une derrière l'autre .
je pense que c'est à cause de exit sub mais je n'en suis pas sur
Si quelqu'un peut m'aider, merci d'avance


Private Sub Worksheet_Change(ByVal Target As Range)

Dim MytargetPart1 As Range
Dim MytargetPart2 As Range
Dim MyBigtarget As Range

Dim Mytargetmdp1 As Range
Dim Mytargetmdp2 As Range
Dim MyBigtargetmdp As Range


Set MytargetPart1 = Union([I11], [I14], [I17], [I20], [I23], [I26], [I41], [I44], [I47], [I50], [I53], [I56], [I71], [I74], [I77], [I80], [I83], [I86], [I101], [I104], [I107], [I110], [I113], [I116])
Set MytargetPart2 = Union([I131], [I134], [I137], [I140], [I143], [I146], [I161], [I164], [I167], [I170], [I173], [I76], [I191], [I194], [I197], [I200], [I203], [I206])
Set MyBigtarget = Union(MytargetPart1, MytargetPart2)

Set Mytargetmdp1 = Union([H11], [H12], [H13], [H14], [H15], [H16], [H17], [H18], [H19], [H20], [H21], [H22], [H23], [H24], [H25], [H26], [H27], [H28])
Set Mytargetmdp2 = Union([H41], [H42], [H43], [H44], [H45], [H46], [H47], [H48], [H49], [H50], [H51], [H52], [H53], [H54], [H55], [H56], [H57], [H58])
Set MyBigtargetmdp = Union(Mytargetmdp1, Mytargetmdp2)



If Intersect(Target, Union(MytargetPart1, MytargetPart2)) Is Nothing Then Exit Sub
If Target.Offset(0, 0).Value = "X" Or Target.Offset(0, 0).Value = "x" Then Target.Offset(0, 0).Value = "X"
If Target.Offset(0, 0).Value = "X" Then
Target.Offset(0, -4).Resize(3, 4).ClearContents
Target.Offset(0, 1).Resize(3, 4).ClearContents
End If


If Intersect(Target, Union(Mytargetmdp1, Mytargetmdp2)) Is Nothing Then Exit Sub
If Target.Offset(0, 0).Value <> "" Then If Target.Offset(0, 0).Value <> "" Then UserForm3.Show

merci