WiiM Mini and Sonos products use different streaming platforms, so you can't use these interchangeably. The only way to group them is to use AirPlay 2. The detailed tutorial can be found here. Use different streaming platforms.
- Play music on your iPhone, iPad, or iPod touch, then control where it's playing from Control Center:
- Open Control Center on your iPhone or iPod touch or iPad:
- Swipe down from the upper-right corner of the screen on iPhone X or later or iPad with iPadOS or later.
- On iPhone 8 or iOS 11 or earlier, swipe up from the screen's bottom edge.
- Touch and hold the group of controls in the upper-right corner, then tap AirPlay.
- Tap WiiM Mini and Sonos. Play one song that you want to play the current audio to.
You can also use AirPlay to stream audio from an app you're using on your device. Open the app, tap AirPlay, then tap a speaker or multiple speakers.
For WiiM Mini owners with Apple devices, you can use AirPlay 2 to listen to YouTube Music. On Android devices, you can use Bluetooth. Then play it directly through the digital (SPDIF) or analog (Line out) output to your speakers.
For WiiM Pro owners, Chromecast can cast YouTube Music to their WiiM Pro device. Then play it directly through the digital (SPDIF, Coaxial) or analog (Line out) output to your speakers.