Bluetooth stacks usually offer only audio output at a time. Some Bluetooth speakers can link to each other to play in sync but this usually requires both speakers from the same manufacturer/model.

I was hoping there would be some sort of device which could pair with multiple blue tooth devices and then stream to all devices while using a single audio source.

One of my bluetooth audio senders can send to 2 at once, but as soon as a second is paired it reverts back to SBC quality so is pretty bad. Also pairing senders and speakers/headphones is always a pain since neither of them really has a user interface to choose the device and mine would always just start to send to the stupid LG soundbar in the next room instead of my headphones because LG think that being always available and in pairing mode is a good idea.

Whats the purpose of such set up? A perm set up? Or just temporary?

You could look at using a mixer with a couple of Bluetooth transmitters as a work around?

Audio Source > Source Output feeds mixer > mixer outputs feed speakers via cable or BT transmitters.

Most mixers have both a "Main Out", "Phones/Monitor Out" and usually a "Line Out".

- you could use both "Main" and "Phones/Monitor" to feed both speakers? (and use seperate bluetooth transmitters on each output)?

- Downside here is both transmitters might have slightly different processing speeds causing havoc with parametric timing! 

Maybe this isnt a workaround after all......

https://www.rockshop.co.nz/shop/live-production/mixers/mackie-mix5-5-channel-compact-mixer-1-mic-line-input-2-stereo-inputs-coming-soon.html

Goosey, your idea worked. I got two BT transmitters, paired with the speakers and then wired them up to the output of the mixer. I used the main output to drive both the BT transmitters as the headphones were not eq'd in my mixer hence the audio sounded too different.

So did end up buying the two Bluetooth transmitters and the Mixer? How much did it all cost you at the end?

Good news!
just be careful not to overdrive....as suspect the impedance level of the mixer output isn’t what the input of the Bluetooth devices are expecting.

checkout the bit transmitter specs to see what impedance their inputs accept and then see what your mixer is outputting.

a lot of people call this ‘high and low level’.

if too high then you care going to get a distortion effect.