Are you looking to purchase other Bluetooth speakers to be grouped and play along with your Wave radio? If your Wave radio is connected to the SoundTouch app, other SoundTouch speakers can connect and be grouped through using WiFi - for group music playback.
Bose systems cannot be included in multi-room playback with other non-Bose systems, using the Echo Dot. In regards to grouping non-Bose speakers for multi-room playback, you'll have to contact Amazon regarding what is compatible. Let me know if you have any further questions regarding this!