Multiple Avi's, 1 subtitle file...

Ok, so I'm sure I'm missing something elementary here, but I have what seems to be a simple problem: I have one movie broken into 2 avi files, with one corresponding subtitle file for the whole deal. The subs work perfectly for the first avi, but then fail to pick up for the second. Starting the second avi and then opening the subs only starts the subs over from the begining... is there some way to get BS to follow thru the subs with a second avi? Without retiming the sub file, or joining avis? Sorry for what I'm sure is a dumb question - just couldn't find an answer anywhere on the site or the forums.

Thanks!
- Dunkelzhan