You could reasonably want to evaluate data in those relations, to compose data to use at the top level. You could also reasonably run queries within the interna

You could reasonably want to evaluate data in those relations, to compose data to use at the top level. You could also reasonably run queries within the internal relations. You could probably be able to promote those relations up on the hierarchy by using them in joins. But I don't think it's reasonable to mix queries of several levels. (I can't even imagine how the syntax for that would look like.)