Audio Focus on Android

I am working on a media-heavy app which plays audio files via the native media plugin, and at the same time should play (HTML) videos which may or may not have audio effects on their audio track.
I realized that the HTML videos, when unmuted, seem to receive the audio focus on android, effectively muting the other sounds and vice versa.
While i could modify the native media plugin to behave differently (which is discouraged, since it might be other apps requesting audio focus) i cannot modify the behaviour of the system web view.
I was just wondering why this is happening, all sounds are played by the same app after all. Does the system web view run in its’ own context? Is there a way of “assigning” it to the current app’s context?

Any hint is much appreciated!