One transmitter, multiple listeners.

what exactly is your question? I'm not clear but that could be just me. Are you asking if Bluetooth can do this...or there technology to allow it? Are the people in a room or auditorium or are they at remote sites? if in the room, their hearing aids should amplify affectively. if in remote sites, don't they use an interface for the deaf/hearing impaired connecting to their phone?

Or is that your asking about group teleconference devices? If that were the case, why would blue tooth be needed?

Off topic, but hearing aids might amplify all you want, I haven't seen a one that handles electronically reproduced sound adequately. I've tried several.

I think this is similar to a tour group. The tour guide uses one transmitter and broadcast his/her narratives to a group of tourist. I don't think bluetooth can do it.