Change Audio Input

Greetings my fellow Volumio users,

I recently installed Volumio and managed to connect my phone via bluetooth to it.
Everything works perfect, but what I want is, that if I connect my phone to the raspberry, the sound of the Webui is getting muted and vice versa.
I tried to mute the bluetooth device with pactl and it worked actually. But I can’t mute the soundinput from the WebUI.
Do you have any suggestions or alternatives?

Sorry for my bad english. I don’t speak english on a daily basis and I need some time to warm up.