If we are talking about an automated rotary indexer using some kind of arduino or similar, and an officially supported mode/process/whatever from Glowforge, the “beep sound” that you mention could be a special audio-signal/code to activate the rotation. Different audio codes could advance the rotation to different degrees.
We have seen so many different ideas for rotary engraving devices. @karaelena just proved the concept of tiny roller-stations working to spin an object within the confines of the space available.
Whether from Glowforge or from the community, I have firm expectations of some type of rotary-index device being available to buy or make relatively quickly once folks start getting their production machines.