Multiple AirPlay streams

for DJay for Mac: Multiple output sources for AirPlay (so you can DJ for say, a home party and have the same music throughout the house using multiple AirPort express and AppleTV units, as well as the output on the computer itself.

Streaming to multiple AirPlay devices is already supported on djay for Mac.

Which djay version are you using? If you have djay 4, please make sure to download the latest update, then click on the AirPlay symbol in the bottom right corner to select the AirPlay devices.