I have an MPG file of an event that contains audio (ac3) and I have a second audio file that is matched up perfectly that contains radio commentary for that event (also ac3). I want to remux the MPG so I have two commentary options *without* re-encoding the video. Basically I want to do with an MPG the move that can be made with MKVToolnix or TSMuxer for MKV and TS files respectively. Is there a program that will do this?

I found a program called Remux that does not re-encode but it looks like the program will only change MPG to VOB but it won't add a second audio track.

Thanks in advance for any advice.