I have a series of recorded lectures that were spoken in English with simultaneous translation into a variety of other languages. We would like to now replay those lectures in English, but also with the various languages.These other languages would be transmitted via short-distance FM transmitters to listeners with FM radios and headsets or other assisted listening devices.

I can easily play the English through the right channel and a 1st language through the left, but is there any software / hardware configuration that would allow for a simultaneous playing a 2nd language track, or even a 3rd?

 Thanks for any advice.