Why sonos S2 app does not recognize sonos speakers on hotspot device?

Power users have the right to demand the impossible, surely?

In order for this to work, the hotspot device would need to somehow section itself off (it’s apps anyway) as a device, a separate IP,  on the hotspot network that it created.  Sort of...walling itself off from the phone network.  Assuming this was even possible for android and iOS  given hardware and all, it would only be useful for the Sonos app and maybe a few other apps. 

Alternatively, the Sonos app would have to communicate via a cloud server when not on the same network as your speakers.  That has it’s positives and minus as well. and probably not something Sonos wants to do just for the infrequuent use case when Someone wants to use their non-mobile speakers in a nonmobile environment, doesn’t have a 2nd android/iOS device to use, and doesn’t want to use voice control….which they don’t currently support.

In hotspot mode a phone functions as a router and DHCP server. It provides private IPs to its hotspot clients, along with its own private gateway IP.

This is entirely separate from all the other apps running on the phone, which -- for obvious reasons -- face outwards, onto its internet connection.