This, in my mind, is the concept of "mesh networks". Small networks (and optionally setup over wifi) Allow clients to use wifi to act as the relay, therefore there can be an interconnected mesh network, with or without connection to the wider internet!
Anyone working on this with nostr yet? There are open source projects for mesh networks that can be used as a goby.
Nostr is so much more than twitter ever was or ever will be. The tools that are coming are a big deal !!!