How do you disable other people from connecting to your speaker while your already connected?

I’ve had the problem of my music getting interrupted many times by my roommate unintentionally since I’ve bought the speaker.

I’ll be playing music, then when he turns his Bluetooth on upstairs it will automatically connect to his phone and start playing whatever is playing on his phone.

Is there any way to stop this from happening?
Can you disable multiple connections?
Or something similar.

I would suggest asking your roommate to remove/forget your speaker in the Bluetooth settings on his phone.