[Help] Ability to overlay sound effect on GTA sounds in helicopters/vehicles

Hi!
I’m looking for an idea on how to change the sound of helicopters to make them more realistic. I’m not talking about changing its sound or custom sounds, but the effect itself, which occurs on some servers.

Upon entering the helicopter, both game audio and player conversations are modified so that the helicopter actually sounds like you’re sitting in it (rather than looking from the outside, even on a third-person camera), and conversations as if they’re through the pilot’s headphones. The sound of the helicopter is different when we’re in it and when we’re out of it - sort of like when you change the camera from third-person to first-person.

While the solution regarding conversations seems obvious - for example, by submixing in pma-voice, I wonder how the sounds that reach the player sitting in the helicopter can be modified.