Custom Aviation Headset Intercom Circuts

Hi Guys, Im new to the forum.
I've been working on a custom intercom circuit that I want to build for Paramotoring. I'm using my Bose A20s rather than using a standard Paramotor Helmet and headsets (basically just a bike helmet and modified ear muffs!), the helmet I'm using in my hold crew chief helmet from my army days. Anyway, I need an intercom circuit for those to function correctly. and I also need to be able to switch between two different radios for transmitting but listen to both, I also want to record all the audio of my conversation in the air when I'm by myself for vlogging and also for when I carry a passenger. I bought a Pilot USA PA200T/A24 Mini Intercom, and it works well, but its missing those extra features that I want. My goal is to have a PCB Printed that has everything in one and is compact. Todo that I need to either reverse engineer an existing PCB or start from the ground up with an intercom schematic and add the parts and features I need. I found one diagram that looks to have what I need however, Its kind of blurry and hard to read. I'm unable to message the person directly that posted it as I'm still new and "Under moderation"

Here is the original thread I found the schematic in

My Circut needs the following features
  • 9V Power Supply
  • Two radio connections with selectable PPT, one will be the Yeasu FTA-850, and the other will be my Ham Radio an VX-8DR, my thought is some kind of quick toggle or maybe a double button PPT remote
  • An SPST Power switch separate from the volume control
  • 3.5mm Audio output to a digital voice recorder
  • External PPT Button input