Airplay devices will only group with other Airplay. Your Mac mini is not streaming with Airplay. My MacBook Pro won’t group with my Apple TV devices either. But it will group with all my other networked devices i.e. all the other DACs I have on my network. So I think your Bluesound will work with the Mac mini but not with the Airplay devices. Also--post your inquiry on the RoonLabs community forum, they are very quick with helpful responses there.