Basically, you can say: One HomePilot® per Google Account.
In case you have registered several HomePilot® on one WR Connect account, you will be asked after entering your access data which HomePilot you would like to operate with the Google Assistant.
You would have the option to unlink the account and then reactivate it to select another HomePilot® after entering your credentials, but since this is not really smart, we would not recommend it.