asterisk users - Jan 2011 - Make ConfBridge hang up on last participant

Is there a way to make ConfBridge hang up on the final participant in a
conference (obviously after some sort of initial grace period)?

Background - I have just moved all of the phones in my house to separate
extensions.  As a replacement for the POTS-style shared line, I have
implemented a "barge in" feature; any internal extension is able to
join
the call of any other internal extension by dialing the extension number
followed by *.  Behind the scenes, I'm using ChannelRedirect and some
additional jiggery pokery to pull everyone into a ConfBridge conference.

In the vast majority of cases, I'll end up with 2 internal extensions
bridged to an external call.  But when the 2 internal extensions hang
up, there's nothing to prevent the external party from accidentally
staying connected to the bridge, tying up the POTS line or racking up
per-minute VoIP charges.

Any ideas on how to address this situation would be appreciated.

Thanks!

-- 
=======================================================================Ian
Pilcher                                         arequipeno at gmail.com
========================================================================