We are using rtpDir bridge as a conference.
rtpDir software is at http://tech.groups.yahoo.com/group/rtpDir/
The latest version v1.23 has the following features:
Runs as Echolink, Echolink conference, IRLP reflector/Echolink conference, and Echolink+IRLP.
GSM and ADPCM codecs are supported.
ADPCM ---> GSM, GSM ---> ADPCM transcoder is included.
Runs on Linux and Windows platforms.
DTMF processing internal(built-in) or External(hardware).
Morse code IDs or Voice.
COS "sensing" or VOX or both.
Support for all link interfaces(sound mode or ASCII mode, VA3TO, WB2REM, G3VFP, G4CDY,...Rigblasters, MFJ, SignalLink,...)
Mark a station as "Mute", "Deaf" or "Mute and Deaf".
Remote text command control or DTMF control.
Timeouts for login, download, connection.
Audio recording and playback.
"Keep alive" heartbeats and RF station identification.
Welcome message(audio, CW or text).
Convert text to CW.
Support for private networks(No Echolink and no IRLP logins, connections,...)
Graphical environment(Linux X11 or MS Windows).
Runs as server or client.
Interfaces with external scripts or batch files.
Runs with or without a soundcard.
Audio signal strength indicator.
Try it with your callsign first.
Once you are familiar with its features,
you can also run it as a Conference.