I think the title says all ...
No, your message is not clear. Is this a feature request or a question?
Mvg, Sander Devrieze.
Sorry for the misunderstanding.
The iaxclient which we use for voip has a "conference" branch which, I believe, is still experimental. When this goes in the head branch we will also have support for voice conferences. Right now it is better to wait for the iaxclient developers to make it stable, both API wise and otherwise.
I added your feature request to the new bug tracker: https://bugs.launchpad.net/coccinella/+bug/141350