CDO Field Merge that is based off of the CDO Unique Code field

Dear Topliner Community,

We have a data card set (several thousands) in a CDO whose unique code is not the email address but another unique identifier. A contact can have multiple data cards in this CDO. We would like to create field merges per contacts who have a record in that CDO, per the Unique codes they have.

Has anyone had an alternative solution other than creating individual dynamic contents per unique code value filtered manually? I have looked into uploading dynamic contents via API but no luck as of yet. If you are able to suggest a way around this, it would be highly appreciated.