He's absolutely asking for some kind of auto-ducking.
I misread that bit none the less should not mean alternatives can't be used
I like it heaps
I use private online rF2 room for testing in this instance so I can test all
F3 SR4L engines without reloading tracks ( you can swap cars in garage )
That way I can watch or let the ai lap for opt..times and without it pausing
like offline does
Same as when I had open online room in rF2 all day 3 years waiting for runners I
would FSW sim sites, watch movies and utube like in pic below
I had to control all volumes separately , hassle
Ear Trumpet makes it easy
The other thing even if there is a app would do it you would not want it disabling everything every-time would you ? So would need manual adjustment anyway
Take different cars and tracks loudness can vary in pits so you may want to change level for rF2 in pic below ...again would need a manual adjustment to the apps settings
Movies or tube are not all the same volume..... again you would need to manually reset the appssettings .......you get my drift ?
So at least with this app you can fine tune all programs quickly and 1 click on any icon will mute it
So pic is server room run offline so no pause when using task-bar with Full screen windowed mode, I can watch utube or movie on top of running sessions, few seconds to re-adjust audio levels for any situation ( Chrome icon is YouTube )