Sub ReplaceTextInGroup()

Dim oSh As Shape
Dim oSl As Slide
Dim X As Long

For Each oSl In ActivePresentation.Slides
For Each oSh In oSl.Shapes
With oSh
Select Case .Type
Case Is = msoGroup
For X = 1 To .GroupItems.Count
If .GroupItems(X).HasTextFrame Then
If .GroupItems(X).TextFrame.HasText Then
' Obviously, you'd run your own replace code here:
.GroupItems(X).TextFrame.TextRange.Text = "HA! Gotcha!"
End If
End If
Next X

' Other Case statements as needed
End Select
End With ' oSh
Next oSh
Next oSl

End Sub