Multi Track Caption Simultaneous Display or Unique Caption Block Styling

It would be very helpful if you could enable multi track display for captions. Alternatively if it is only possible to display one caption track at a time have caption subtracks/child tracks that can be individually styled differently from the parent track.  If that is not a possible at least a feature to apply caption styles to individual caption blocks rather than entire tracks to achieve the above described functionality. 

This could be immensly benifficial and save a tone of time and error captioning multiple speakers that step over each other, instead of having to style each caption track, often repetitively, individually, the user could style multiple blocks at the same time applying saved styles with one click to each track or a group of selected caption blocks.