"and No, keeping this info outside of Lacerte does not work well, doing it now."

You have SDK to relational databases, already, here:

https://proconnect.intuit.com/community/lacerte-sdk-group/gp-p/501

https://developer.intuit.com/app/developer/lacerte-sdk/docs/lacerte-get-started

and example info:

https://proconnect.intuit.com/community/lacerte-sdk-group/custom-fields-or-what-my-options-are/gpm-p...

https://proconnect.intuit.com/community/lacerte-sdk-group/table-of-codes/gpm-p/969

https://proconnect.intuit.com/community/lacerte-sdk-group/linking-tables-in-access/gpm-p/1476#M111

https://proconnect.intuit.com/community/lacerte-sdk-group/odbc-connection/gpm-p/967#M101

That would do what you asked for, and Intuit already provides for it. This is ODBC.