In the case of a direct Bluetooth connection to a Teufel streaming device, the sound signal cannot be transmitted to other Multiroom speakers via Bluetooth, as synchronous playback cannot be guaranteed for technical reasons. This is because Bluetooth does not offer a signal feedback function for synchronization. For the Multiroom option, simply switch to WIFI transmission via the Teufel Raumfeld app.
Alternative: Connect a Bluetooth receiver to the Line In of a Teufel streaming device and distribute the Line In signal (also requires WIFI).