Hi Brent,
Thank you for posting in Microsoft Community forum. I understand that you're trying to retain two files where the original file will act as "master file". This is not possible becase once you copy a file, it will no longer be connected from the source file. Instead of copying the file which will make the file a separate file, I would recommend creating a shortcut of the master file to their personal Onedrive. You may follow the instructions from this article.
https://support.microsoft.com/en-us/office/add-...
Additional reference: https://answers.microsoft.com/en-us/msoffice/fo...