Play audio files out of multiple channels of hardware audio interface

I would like to play an audio file from multiple outputs of my hardware audio interface (Focusrite Sapphire 18i20).
My goal is to programmatically send a sound file to different speakers.

The archive suggests ofxPd, but that addon seems out-of-date.

Any suggestions are most welcome.

As I couldn’t find more information, I will use Max/MSP to do the audio routing to the interface, and send control data from openFrameworks via OSC.

It’s a pity this functionality is not a core part of openFrameworks…maybe my perspective is biased, but routing audio would seem like a fairly reasonable requirement…?