Multiple audio inputs

I need to run 3 mono audio inputs into my asterisk system, and allow callers to pick one to listen to.
I know that I can (in theory, I’ve never had much success) route a call to the console channel to listen to line in audio, but I’m not sure how this would work with 3 separate channels.

A little background on my project, I’ve been tasked with setting up a system for a cable access television station to allow a producer doing a live shot in the field to call in, and be able to listen to the intercom feed for one of our three TV studios. Bidirectional audio would be a plus, but we only need it to go one way right now.

What would be the best way for me to do this?
Multiple sound cards and multiple console channels? Softphones?

The industry-standard way to do this is to use an auto-answering telephone hybrid like this - but I’d prefer an asterisk solution, if possible.