Is it possible to create a proximity app for a massive concert?

Hi, i run an agency based in Mexico City and i would like to know if the beacons can be used for a “Lost friends app” in a concert. for example creating a group once you have the app installed and then if a member gets lost send their location via beacons so the other members of the group get the location on the map inside the app, so they know where to look. this idea is for a bigger than a stadium location, and i understand the need of a lot of beacons. Also, if this is possible. How many simultaneous connections a beacon can handle?

The main idea is to run without the use of 3g, 4g or any carrier data connection, because in a concert it gets saturated.

Also if there is any developer interested in this project we can talk to get an estimate
Thanks in advance!

Intriguing idea… were you able to build one?