Create relationship between Form / Subform after import

I have imported our customers and their addresses from 2 separate files into zoho creator. I now have two forms: one customers and one addresses. I have defined addresses as subform in the customers form. What I haven't found out however is how to restore the relationship between customers and their addresses. The data was in an access db before and relationship was through a primary / foreign key 1-n realtionship.

Thanks for any hint on how to achieve this (also by deluge scripting, if necessary)