Location Based App Access restriction?

I frequently have family and friends over to my house and as I migrate more of my home control to the iOS app, I would like to provide these guests iOS app access. What I don’t want is for them to be able to control anything while they are not physically at my house. Whats the best method to accomplish this?

Only set up the app with your local IP and don’t setup the external Ip

makes sense. Thanks for the comment.