I think we need more information about the purpose of this request. Can you explain why this is required and whether you will only ever have three documents in total?

Paul's answer is factually correct but probably not be the best way to do this if the end result is going to be three documents for 'A' and ANOTHER three documents for 'B' since the links in the 'B' series of documents are going to be pointing back at the 'A' master doc. The links are also problematic if the master doc is renamed or moved to another folder or the user editing the master document doesn't pay attention to where the bookmark contains after edits are made.

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Andrew Lockton
Chrysalis Design, Melbourne Australia