Get word 2003's comment relation

[Fish \(Yahoo\)]

How do I programming get the comment relation?

Example:
User1 adds comment in Word. You could see "Comment [User11] :.....".
User2 click the User1's comment then adds the comment . You could see
"Comment [User2 2R1] ....".

Comment Object do not expose the relation between User1's comment and
User2's comment.
How can I get it?

Thanks.