Right now you can only filter a Many->One relation of an object by another data collection, query or same as or not the current user. I think it would be helpful to be able to actually define a record/s in the filter without having to go through the extra step of defining a query or datacollection. The will come in handy in the new advanced data filter widget we are working on now that gives frontend filter and sort options to the end user and it will not make sense to them why you couldn't select one of the options to filter a many->one connection by.
Current options for filtering a many->one field

User should be able to select an option here and see only records that match...but currently we do not have a condition to filter many->one records.
