asterisk users - Aug 2007 - transfer/conference

Hi All-
I have an asterisk server and GXP2000.  If I want to send a call to  
someone else (external), I can transfer the call where I can announce  
it, and then send it over.  But what I'd like is to start a 3-way  
conference, and then drop out.  But if I do a conference button on  
the phone, and then drop out, the other two are not left to finish  
their conversation (the call is ended).  Should I be using the MeetMe  
application instead or is there a different way to fix this problem?
  thanks
    Todd