[asterisk-users] custom automated meeting

[Thanasis]

I just want to make two specific sip phone sets to ring together, when
someone dials a specific incoming extension. And then, when each of the
ringed sets answers, to be placed immediately into meeting session with
the caller together with the other phone set.

Here is exactly what I mean:

Person A dials 123456789. Asterisk routes the incoming call and rings
sip phones B and C. Person B answers phone B and starts talking with
person A, while phone C keeps ringing. A minute later, and while A and B
are still talking together, person C answers phone C, and starts talking
with A and B together (that is aromatically all being placed in the same
conference session).

Is that doable?