Slide presentation virtual background and 3 on screen presenters. Help?

[mikeatrye]

hello! We are trying to figure out the best way to achieve the following:

We have a slideshow we want to share during a presentation. Ideally, it's the virtual background. We have 3 presenters who will be speaking throughout the presentation. We'd ideally like them to be on top of the slide show (ala the keynote slideshow as a virtual background) ... would settle for being able to have the virtual slideshow present and these three presenters "pinned" in someway beside the virtual slideshow. The virtual slideshow should be 1/2 the screen approx. and the three presenters can occupy the other half of the screen (stacked) etc. 

If this isn't possible, is there a way to control the VIEWERS screen layout who are attending ... that would allow me to at least share the presentation and ensure these three speakers are visable on the sidebar and the sizing is correct etc. without having to try to walk the participants through clicking on various settings etc.

THANK YOU!! Third part apps welcome -- whatever needed to achieve this!