Running Music Sync App

Just wondering if such an app exists that allows a group of people in close proximity to each other (i.e. running together) to synchronise their music so that they are all running to the same song in sync. Either such that they have to have matching playlists on their iphones and a 'master' phone sends play/skip/pause commands etc, or a server/client type thing where the 'master' iPhone streams what its currently listening to to the others.

Anything sound at all like this?

AirPlay

Using the app found here you can turn the other devices into AirPlay speakers and stream the music between them. As far as this goes, you can only do it for 2 devices, but it's the best solution I've found.