Sonos Amp- Dual Sub Daisy Chain?

I have a Sonos amp in a media cupboard. I’m planning to add a sub about 2 metres away. My understanding is it will need to connect directly to the amp’s 5ghz signal. I think this will be fine despite the cupboard? (I could hardwire this sub if necessary). My question is if I want to add a second sub to the same amp, will the sub daisy chain off the other sub which will be in the open within about 4m of it or does it have to go off the amp which will be about 7m in a cabinet (and I assume too far to hold a stable signal and I cannot hardwire).