[asterisk-users] Intercom mode on Polycom and/or SPA9xx

[C F]

I have a customer that is used to Intercom from ther Avaya system,
where you just page someone and until they don't pick up the handset
there is only one way audio from the caller to callee.

At the moment I'm using for the Polycom ALERTINFO to a customized ring
that auto answers, and for the Sipura spa941 SipAddHeaders that also
autoanswers however they both do 2 way audio, is there anyway that it
can be configured to 1 way audio?

I know that I can do meetme with mute, but that wont work for 3 reasons:
1. Unmute will only work with a DTMF, which I realy want handset to do it.
2. Xfers wont work as I want, since I'm using the intercom on attxfers.
3. My boxes might or might not have the power to handle many meetmes,
and I don't want to run into this.

Thank You