How to disable a sound from second locomotive in the cab?

[awaken1977]

If I ride in ES44 (for example), I hear sound from second unit , while in the cab. Two sound sources on the same frequency blended with each other, creating unpleasant effect of "phasing" or flanging. Also, it makes sound more noisy and dirty . I understand that, if loco sound is disabled for cab camera, it also will be muted for traffic.
Is it possible to have 2 things simultaneously:
-loco external sound disabled in cab, when it is in player's train position, other than head end.
-but loco sound enabled in the traffic, so I hear trains passing by

[BNSFdude]

If I ride in ES44 (for example), I hear sound from second unit , while in the cab. Two sound sources on the same frequency blended with each other, creating unpleasant effect of "phasing" or flanging. Also, it makes sound more noisy and dirty . I understand that, if loco sound is disabled for cab camera, it also will be muted for traffic.
Is it possible to have 2 things simultaneously:
-loco external sound disabled in cab, when it is in player's train position, other than head end.
-but loco sound enabled in the traffic, so I hear trains passing by

I'm afraid that you can't change this. It would require you making a whole new xml for the engine audio.