Does the API allow you to join queries across data types

I have seen several people here asking to have easy ways of doing things like getting a return set of all volumes from a publisher, or all issues from a volume. It seems like even when you do things like query for all volumes, you cant drill into the publisher object to filter on the publisher ID. This would make it so much easier to filter and display naturally grouped data items.

Is this something that exists and I'm just not seeing it? If not, is this something that could be added?

Thanks!

I don't think this is possible, no. You can filter against values contained within the given resource, but you can only directly access one resource per api call.