Starling Home Hub is commonly used by customers with multiple homes.
Due to the way HomeKit works, a single HomeKit device (like Starling Home Hub) can only appear in the HomeKit Home it’s physically located in. This means, for example, that a single Starling Home Hub cannot place some devices in one HomeKit Home, and others in a separate HomeKit Home.
If you have multiple Nest Homes, when you set up Starling Home Hub, you'll be prompted to choose which Nest Home to connect to your current HomeKit Home. (You can change this choice later by going to the Starling Home Hub app, Nest Home and Product Settings.)
As a convenience feature, Starling Home Hub also gives you the option to import devices from all Nest Homes in your account into your current HomeKit Home. For many customers, this avoids the need to purchase another Starling Home Hub for a second home.
If you have two homes, and you want Nest devices physically in home #1 to appear in HomeKit Home #1, and Nest devices physically in home #2 to appear in HomeKit Home #2, you will need one Starling Home Hub in each home. Both Starling Home Hubs can be signed into the same Google Account (or Nest Account) without any problems.
If you have any other questions about usage with multiple homes, please contact Starling Support with a detailed description of your set-up, and we'll advise what configuration is most suitable for your situation.