Combining multiple undo groups (from other macros) into one big group.

Hello, all.

A question for the gurus. I have been using the now classic VBA Undo Group tricks on most of my Macros with excellent results. Like this:

Sub boostStart(Optional unDo$)
    On Error Resume Next

    'Thanks for the cursor, Shelby!
    If Len(unDo) Then ActiveDocument.BeginCommandGroup unDo
    Optimization = True
    EventsEnabled = False
End Sub

Sub boostFinish(Optional ByVal endUndoGroup As Boolean = False)
    On Error Resume Next
    Optimization = False
    EventsEnabled = True
    If endUndoGroup Then ActiveDocument.EndCommandGroup

End Sub

And it works great. But I have run into a bit of trouble if another macro also uses it. For example, a commercial one that is locked up, but allows for calling its functions.

So if I have my own macro that does something to the document, then calls the outside macro that seemingly also calls "Optimization" and or "ActiveDocument.EndCommandGroup" the Undo becomes a mess with some parts being nicely grouped, but others not. Is there some other way to create an undo that works like a straight up copy of the document before an action and then returning to that point of necessary? Sure, saving works, but the risk of forgetting that (user error) is always a concern.

Thank you in advance.