Thanks for the question. Yes, if:
- You're using an audio source:
- Selected from within the MusicCast app (DLNA server, Internet Radio, Spotify, Pandora, Napster, local device music library et al)
- Directly connected to a MusicCast player/tuner/AV receiver device on the same network (HDMI, Optical, Phono, Coax, USB, CD, AM/FM etc, depending on the device)
- There's good WiFi coverage across the different rooms
If, instead of using the MusicCast app, you connect your phone or mobile device to a MusicCast speaker using normal Bluetooth or Airplay, it's not currently possible (as of late December 2017) to choose multiple MusicCast speakers. Mac users may be able to do this, however, depending on the version of iTunes/macOS installed.