We've currently implemented a relationship between a Standard-Custom object via DCL, Custom object records is tagging a record from the standard object (Account). Searching a custom object record in the custom object workspace using an account filter would work, however searching an account in account workspace using any of the custom object field is not possible unless we'll build a relationship via reference Customer-Standard object but cardinality can only be 1:1 or 1:M picking any wouldn't follow the same relationship as the original and would cause conflicting logic.