Ring multiple users simultaneously with one common extension and add them into a conference

We have a startup venture in Asterisk with a WebRTC client and a SIP client.

We have the following details:-

We re trying to have a conference between webrtc and SIP endpoints. We are using Asterisk as the PBX with Bria as one of the SIP endpoints.
We have a common extension which has 3 Phantom extensions behind it. The Phantom extensions have individual users logged into and registered to the PBX from SIP or Web(local).
When a call comes in, all 3 users must ring simultaneously. When one picks up, the call should get established with the other Phantom users still in ringing state. They should be able to join to the conference once they pick up the call.
We are trying the same on Asterisk 13.0.
I request if anyone can help us on this since we have been stuck on this since quite sometime. Any help is much appreciated.
Thank you in advance,

Naeem Elham

This sounds messy, but have you tried a call queue with the strategy of ringall and an attached AGI that would originate a call from the other two phones using ChanSpy in whisper mode? The problem is that once the call is answered, the system won’t continue to ring the other phones. You could also write code to use a DTMF in the call to transfer the two legs into a bridge, but something will have to pull the other two phones in.

Found this too…

https://www.voip-info.org/wiki/view/Asterisk+n-way+call+HOWTO

I would write a small AMI application to perform following
(1)Monitor AMI events for specific incoming calls.
(2)Place incoming call into dynamically created conference (either through dialplan or AMI application)
(3)Originate calls for your 3 phantom endpoints from AMI application.
(4)When call gets answered, put them in the same conference where you have your incoming call.

I’ haven’t got a chance to work on ARI, but that too looks suitable for your requirements

–Satish Barot