Caller ID through 12 volt interrupt on whole house audio

["Greg" <greginsarver@xxxxxxxxx>]

I have a Russound CAV6.6 whole house audio system which supports 12
volt interrupt input which will mute any existing audio source and play
some sound over all speakers (for example, tehy have a doorbell module
which mutes everything, regardless of which source you have on, and
plays the doorbell sound).

What I am looking for is a way to have caller id numbers or names
spoken over the house speakers and have it done with the 12 volt
interrupt (so that I can have any source on and the caller ID will
still come on).

I looked for a pre-made module to do this and don't see anything.  I
have caller id software on a server that supports text-to-speech (which
is also a source for the Russound system) but don't know how to make
this go through the 12v interrupt (if I make the caller id a source on
the Russound system, I would have to have that source chosen to hear
it).

Thanks for any suggestions