Bluetooth isn't really set up to create the kind of system you want to do.
The way to do it is to use speakers from Sonos, Denon, or BluOS. They operate via WiFi and tablets and phones are used to control each zone not just to stream to the speakers. The speakers do the streaming. Speakers can be used in mono or stereo. They also make streamers that can connect to any existing audio system and a powered streamer that you can connect the speakers of your choice. You can use in wall speakers to create a neat look.
If you go with the Denon Heos system you can also use Denon or Marantz receivers for better sound and home theater. Heos streaming is built in.