How to related on non-PK?

So, I have a Projects collection with a UUID for a PK and a second field called “monday_id” which is BIGINT, unique and indexed… I want to create a relationship to Projects from “Project Subitems” using the “monday_id”, NOT the Projects PK. Is this possible?

This is not possible today (v11.8.0). Directus relies on the table’s primary key to setup the relationships.