Change border color of grouped element

Hi all,

I've written a macro which changes the border color of a shape in Powerpoint (toggling between pre-defined colors).

Now, this works fine, however, when a shape is grouped, the macro won't change the color of the shape (it will only change to black once (because of the ELSE statement) ).
Ideally, it would change color of the borders of all members/shapes in the group.
Ideally, one would select the group, and run the macro, and the outer shape changes the border color (Also see attached dummy powerpoint).


Does any of you know how to re-write the below to suit this?

Public Enum Color
        PADPurple = 13964777    'RGB(233, 21, 213)
        PADYellow = 49407       'RGB(255, 192, 0)
        PADBlue = 15773696      'RGB(0, 176, 240)
        PADBlack = 0            'RGB(0, 0, 0)
    End Enum

Sub ChangeBorderColor()
    'This macro can be used to quickly change image border colors in Powerpoint.
    'It's advised to bind this macro to a keyboard shortcut (i.e. CTRL + > )
  On Error GoTo Errorhandler
  
    Dim myPic As ShapeRange
    Set myPic = ActiveWindow.Selection.ShapeRange
    
    Dim CurColor
    
    If Not ActiveWindow.Selection.Type = 2 Then
        Debug.Print ("Selected object is not a Shape type")
        Exit Sub
    End If

    'Retrieve current border color
        CurColor = myPic.Line.ForeColor.RGB
        
    'Change color
        Select Case CurColor
            Case Color.PADBlack
                Debug.Print ("Black > Purple")
                myPic.Line.ForeColor.RGB = Color.PADPurple
                
            Case Color.PADPurple
                Debug.Print ("Purple > Blue")
                myPic.Line.ForeColor.RGB = Color.PADBlue
            
            Case Color.PADBlue
                Debug.Print ("Blue > Yellow")
                myPic.Line.ForeColor.RGB = Color.PADYellow
                
            Case Color.PADYellow
                Debug.Print ("Yellow > Black")
                myPic.Line.ForeColor.RGB = Color.PADBlack
                
            Case Else
                myPic.Line.ForeColor.RGB = Color.PADBlack
                Debug.Print ("Unknown color > Black")
        End Select
        
        
    Debug.Print ("Color changed")
Errorhandler:
End Sub

Thanks in advance!
A.