Relation and Entity Share a Field / Reference Each Other

I can't seem to get this to work. I've searched and search, and maybe I'm not using the correct terminology, but I need to add a custom field to a Relation that reads a value from the Entity its related to. Or another way to put this, I need a field from the Relation to update a field in an Entity when the Relation is updated. Example:

Entity -> Worker
Relation -> Employed At
Entity -> Company

I want to update my custom field "classification" through the Employed At Relation and then see that change reflected in the "classification" custom field in my Worker Entity.