I think organizers of FlyerTalk gatherings are more likely to be successful if they have actually already attended some FT gatherings, or at least met up with a few other FTers! I'm guessing that with a March 2009 registration and 2 posts, the OP has not. (But of course I could be wrong.)

Also note the "must be open to all" proviso as mentioned by Jenbel above. You can't block anyone from attending on the basis of their (too old) age or non-elite status or anything else. However, you can always choose an activity (rave? frat house blowout? ) that you think would mainly appeal to the demographic you have in mind.