It sounds like what is happening is that you are working with a multiple Title/PGC VTS. If this is the case, the correct procedure is to duplicate the ifo structure just like the original is. Don't look at the vobids, per se. Look instead at the Titles (TTNs) and PGCs. You need to have one .m2v for each PGC you have in the ifo, and a corresponding audio stream. Reauthor using a good authoring program, making sure to create additional Titles and PGCs to where your reauthored ifo mirrors the structure of your original ifo.