Porthole is now scriptable
June 2014
Porthole version 1.7.0 came out two days ago. It introduces scripting, a feature that’s been requested more than once.
Being able to use AppleScript to control Porthole means that you can automate and toggle certain functions of Porthole without going through the interface. Which is pretty awesome!
Update to the latest version from within the app, or download a fresh copy from the website. Then read the tutorial on scripting to get started.
Porthole
AirPlay all audio to multiple speakers
Play all audio from your Mac through multiple AirPlay speakers at the same time.