How to play music on two bluetooth devices

Hi there again,
I am working on an private app for my custom vehicle, where I would like to use two bluetooth (music) boxes, bc the motor is kinda loude, to play some music/sounds.
Now I am wondering if, and how I could play music via Bluetooth on two devices? Can I do this with AI2?
(Or is spotify already able to do this)

Thanks for your time in advance!