Hi
Yes, it will work. I did the same thing (but using an Up2Stream Pro V3) to connect a Yamaha digital piano. The audio from the piano was played on all other Amps (all Up2Stream Amp V4) but there was a significant delay. The ADC has to convert to digital, the pass the signal around the network, then the DAC needs to convert back to analogue for your speakers.
See my post here Whole House Audio
I do something similar with the turntable too, using an S50 Pro+ and again, there is a delay, but it works perfectly well.