The best I saw out there was a 2 device pairing but only one in use at a time.
I have the Alexa Dot, and for me it's the cat's meow for space and how I can hardwire it to my system.
I have 3 PCs w/Bluetooth, and Alexa w/Bluetooth and any other BT device I might want to connect. I want to connect them all to one set of speakers. With the latest tech out there this should be easier. Right now I have an Audio Mixer with 3 BT Audio receivers plugs to 3 input chan. I have the speakers hooked to the output. Would like to go wireless to speakers. PCs and Alexa all connect to the separate BT receivers. What I need is a 4 chan BT mixer with the receivers built in and a BT transmitter on the output. Or am I missing something and there is an easier way???

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic