Audio Multichannel audio routing

Hi everyone,
I'm running on a issue trying to persue the following project: I'm developing an interactive solution with unity, consist on a round touch table with 6 speakers around. I need that each interaction that a user make have a sound response on the closest speaker where he is working on. I made a graphic so you can understand better.
The concept is basically put virtual microphones where the physical speaker will be and route each one to an specified channel output (I have a 5.1 soundcard)
How can I get an aproach to this?
Thanks!!