Hi Liam,
I am the product manager for wireless systems at Line 6. FYI the support forums on our website are staffed and we try to respond the same day as you post a question.
Now to answer you here, The G50 like all receivers will only receive from one transmitter at a time. But the channel selection on a G50 receiver is done via a simple rotary switch on top of the receiver. If you placed the receiver within arm's reach or on top of your amp, you could easily switch in a second or so between the basses as you switched without having to power up and down the transmitters.
Best of Luck,
Steve Devino
Line 6 Product Manager Wireless andLive Sound.