Participants in Breakout Rooms annotating on a slide shared out by the host

I need to be able to have my learners (who are on Smartphones) annotate a slide I have shared out to  their breakout rooms (as a host). I know the share out from the main room to breakouts is new, but is the annotation option not available for that feature yet? Is it planned as part of an update?  

My workaround has been to provide a link to the slide to all learners, but many struggle with sharing URLs  in their breakout rooms , so I was delighted when the option to share out came along as a timesaver in class.