Here's an update:
we've been talking to one of the developers on the GTalk team regarding the conference call method we've been testing, the feedback we received was to try it out with more than 4 users... whcih we're currently working on.
Theres also some one who's written a chat bot for gtalk that supports texting more than one user at a time. This hasn't been tested out yet. You can find out more info about it
here.