WAIT A SECOND!!
Sorry paparazi, I think you are getting "closing session" confused with "closing disc". You can write multiple sessions to a CDR. If you close a session, you should be able to add another later. The problem huronbay is probably having is that they're closing the disc. Once you close the disc, then you've sealed off the TOC (table of contents) and it won't allow you to write anything else.
Hope that helps...