Aah, now this is much clearer.
Now I'm not an expert in RF design, especially in those frequencies, so the easiest solution would be to have a seperate antenna each RX.
If you can't do that, you could try just directly connecting the antenna to each receivers, though I doubt you will get good results with this. It might work, but with sub-optimal reception.
The best (I think) would be a divider circuit (like a "cable splitter" for TV signals, which is just a transformer and a bunch of connectors) or maybe a pre-amp after the antenna, feeding the three receivers at the right impedance.
I like the 3-antenna solution best p-)
Good luck,
Christian