Suggest a good method for extracting audio tracks from a dual audio divx?

I have a few dvix movies with dual mp3 audio that are too big to fit on CD -- overburning isn't working. I'd like to extract both audio tracks as mp3, then recombine the video with just the primary track. I know how to extract the mp3 from a video file with one track, but I'm not quite sure what to do with two. I don't want to grab the uncompressed audio and reencode. The tools I typically use are nandub and graphedit, but any explination of a method that does what I want is appreciated. I haven't tried too hard yet, so forgive me if this is ridiculously simple.

Im not entirely sure, but I think you could extact the video, audio1, and audio2 from the source. Then you could recombine the Video with whichever audio you want in NanDub. You can do this in Graphedit, search the forums, there are plenty of posts on how to extract audio with Graphedit.

#4 in the audio FAQ explains how to do this with nandub. Thanks.