Hybrid Rendering Functionality

I work on huge projects with many light sources. Imagine a stadium concert with 50+ spotlights and emission meshes. Ideally, I'd like to use volumetric lighting to add realism to the scene. However, since this is a video project, it could easily take over a month to render! While Cycles is a must for rendering everything but volumes, I would like to be able to render light beams passing through a volume with Eevee. Currently, I can do this by rendering the first pass in cycles without volumes, then using 'holdout' on all non-light objects in Eevee, and then screening the Eevee render over the Cycles render, but that's time-consuming on big projects.

I would like to see the option to selectively assign a different render engine to objects like volumes so that the render can be done in one image. Is this possible?