This is new for me. The text of the linked page say that it is for Relay G50/G90 Systems.I think about to buy a new Sender for G30 for an additional guitar . This would be a good alternative.
Is it possible to work with both transmitters (G30, G50) on different guitars. Of course only one guitar would be switched on.
It works as Ingolf said.
And it even works the other way round (G30 transmitter to G50 receiver), which resulted in the most confusing soundcheck of my life I was playing a G30 into Kemper and the main act, who had done soundcheck before, had a G50 into Kemper and left it all on. Therefore I way playing through both Kempers as we had set the same channels set on the Line6. Took us about 3 minutes to realise, where the second sound came from...