I'm trying to find a good guide on how to set up the following scenario:
1 - Raspberry Pi presents its own SSID to clients as a hotspot for to serve up local resources (airplay, automations, etc.) but not internet access (this should be as simple as leaving out the router address, and phones would use their own 4g connection to get internet).
2 - The same Raspberry Pi, using a second WiFi dongle, could optionally connect to another SSID when available for internet access, and could ideally can share that internet access to clients using the SSID in item #1.
Can anyone point me to a good guide on how to do this? Google searches often return results that are close but not quite what I need.