Since you don't route audio signals via wires in Isadora, it's tricky. (Unless you do use AU audio actors)
You can do a mono file and pan it to the left with movie player, so your sound goes out from one speaker only. If you want movements across several speakers, you have to premix them on multichannel audio file.
(But if you want to adjust you have to rebounce and remux your mix again.)
To do a multichannel audio file :
Export each stereo pair to an AIFF file (Front L-R, Middle L-R, Rear L-R by example)
1. Open first one with quicktime
2. Open second one with quicktime too
3. Select all on second audio file window (Cmd+A)
4. Copy (Cmd+C)
5. return to first audio file window (playhead at the begining of the file)
6. Add to sequence (alt+Cmd+V)
7. Do 2.3.4.5.6. with the third audio file
8. Now when you ask infos about first audio file (Cmd+I) you can see several stereo audio streams.
9. Save as...
Now you have a multichannel quicktime file you can open in Isadora.
Each stereo pair will be routed to each stereo output. (e1-2, e3-4, e5-6)
Best
Philippe