Master-Slave synchronized apps

I dream of the day when the leader or pastor is using a Scripture App which not only highlights the text on his own (master) phone as it is being read/played, but also keeps other people’s (slave) Apps in sync with the master App. I imagine this could be useful for both scripture readings as well as for songs.
It could potentially eliminate the need for fancy data-projectors completely.
Am I just dreaming, or could this happen one day?