Extend Wiimote Range? (Bluetooth, not IR)

I work in a venue where we have set up a Wii for customers to play, with the Wii console securely locked away in an office, and a wireless sensor bar stuck to the bottom of a projector screen in a nearby room (approx. 15 metres away). With a good quality projector and great sound system, it works a treat!

However, we have now added another projector/screen at the other end of the venue and are having trouble connecting the wiimote to the console at this increased range. It's only about another 15 metres but the controller loses connection with the console at about 20 metres...

I've searched the internet high and low for terms like 'wiimote range extend' but all it turns up are people talking about using homemade wireless sensor bars, which we have already done. What we're trying to do is boost the bluetooth range of the wiimote, but I'm not sure if it's possible. I'd be up for some modding if it's possible to achieve by changing something within the controller or console, but if it'd be possible by buying some sort of bluetooth range extender then that'd be preferable...

If there is a way to achieve this, please let me know. I can't be the only one wanting to do this, as I've seen people playing Wii in cinema screens and can't imagine they are all able to have the console at arm's length when they do so... :)