I have two daughters! (combined audio streams in media_player using browser_mod)

Hei there!
So I have 2 small daughters, who both require constant watching. I’ve setup some Tuya cameras to watch them sleep (one in each room) and found some limitations, namely that the sound doesn’t mix between the 2 cameras. So I wrote an Android app which fetches those video inputs.
But again, the sound source is set by some native function and will only go the “call” audio output, which doesn’t work well when mixing 2 sources.
So I found some old phones, installed the “Cool mic” app, installed an icecast2 server on my raspberry pi (which is also running HA). And then I wrote another Android app, which streams from those 2 “mount points” into the default Android audio stream (which does accept mixing). So yay, problem solved, I can watch my daughters using the homewritten Tuya app and I can hear them using my homewritten app which streams those icecast streams.
Except… Well then I found out about browser_mod and wanted to use it. My project is to have an automation that will trigger listening to daughter 1 when daughter 1 is put to sleep, listening to daughter 2 when daughter 2 is put to sleep and of course listening to both at the same time when they’re both asleep! And all of the above while listening to regular radio like BBC or something.

So while I think I can rewrite my audio app to be triggered by my automations, I thought it might just be less painful to try to make a 3rd mount point which would do the audio mix of the audio streams of my daughters. So I’ve installed liquidsoap because according to a random guy back in 2013 it’s easy to mix 2 audio streams into 1. But I never got it to work, unfortunately. All I got was a soundless stream on my new mount point.

And that’s when I discovered browser_mod. I wanted to give it a try because I thought it was fun to use HA companion as a “launcher” app on my Android tablet and use browser_mod to stream from various internet radios (including my local streams).
So unfortunately my setup is not working the way I want it to work because obviously starting a stream on a media_player will stop the previous one from playing. That’s the intended behavior in most cases.

But I thought maybe someone else also had 2 daughters or a similar setup and maybe would be willing to share some ideas! I’d be happy to share what I have, but I have to run now since daughter 2 is crying!