I guess this is not possible then let’s make this a request.
I would like to link tables using any other than the primary field.
Real life example using Airtable as a special, small biz CRM:
table 1: customer database, customer account number is primary field, other fields like email
table 2: orders, linking to customers via account number
table 3: form submissions running in from a web form, customers don’t use their account numbers of course (mostly even don’t/need to know them). I know would want to query the customer DB using the email field to see if there’s an account for that email and then link it,
If it’s possible it would be great but it doesn’t look like.