Factory overhead Onstar Microphone

[Sethorama]

Okay i just recently installed a Avic-f90bt.

I used a pac-0s4 and axxes ASWC

My truck came facory with onstar bluetooth and handsfree calling.

My new unit has bluetooth and a aftermarket mic.

So currently i have 2 mics in the truck the factory and aftermarket....

one for the bluetooth one for the cd player.

Is there a way i could tap into the overhead console or is there an adapter or some type of solution!

Edit**]

this is a 2010 silverado 5.3 non bose