Can originals be in a separate workgroup or disabled from workgroups all together?

Question

We are using Perforce streams, the Perforce workgroup plugin, and Unreal 4. This means that our projects live in a Perforce stream. However, we want to keep the Originals stored in a separate, non-branching location.

If we specify an originals location outside of the stream, we get 'not in client view' perforce errors. I expect this is from the stream workgroup being updated for every original file.

Ideally, we'd like to have two workgroups. One for originals, one for the project. Failing that, we'd like to have originals not be in a workgroup at all.

Is there a way we can accomplish either of these?