Bake only lighting from emitter meshes (Cycles)

Is it possible to bake only the direct lighting and global illumination (GI) from a set of highpoly meshes to a lowpoly? Here’s what my models look like (highpoly first, lowpoly second):

What I want to do is bake the blue lighting coming from the emitters to an otherwise mostly black texture (similar to this). Is this possible to bake with Cycles?

I’ve tried baking this a few times already with most of the options in the Cycles baking options with no luck. None of the bake types seem to work out well when the non-emitter is black, so I don’t know what to do. Is there a way to work around this or do I need to try to do this with some other renderer entirely?