I second the recommendation to use an external notification service that can be called from either hub. I use a self-hosted notifications server, Gotify (which is Android-only), but there are a lot of options. One of the simplest, which I also use as a backup in case my Gotify server is down, is to use the email-to-SMS interface for my cell provider to send myself text messages from the hub. This takes care of notifications with no additional apps or services needed on your phone. I use this app to send the emails: Sendmail - Send email and text notifications, (notification device) no local server needed
You mentioned Android and iPhone presence... I don't have a solution for iPhone, but multi-location geopresence should be easy to do using Google Home. You can set up routines for 'when I arrive at a location' and 'when I leave a location'. Have those routines activate a 'virtual presence with switch' device in either home.
The Google Home app has provisions for multiple homes, but I'm not sure if that means it can connect to two Hubitat hubs at the same time. However, you could still make this work with Rule Machine and Maker API even if you can only connect to one hub.
Assuming hubs 1 at home 1 and hub 2 at home 2, but Google Home only able to control devices at home 1, the sequence is:
- Arrive at home 2
- Google routine turns on a virtual presence switch on hub at home 1
- Rule machine on hub 1 triggers based on that switch, calls Maker API cloud endpoint to turn on virtual presence switch on hub 2
- The opposite happens when departing home 2. The routine turns off the switch on hub 1, which triggers Rule Machine to call the Maker API cloud endpoint to turn off the presence switch on the second hub.
