There is a way for a HomeKit controller (iOS, Apple TV, etc.) to give access to other controllers (i.e. our gateway), but that process is undocumented, so I had no idea how to implement it. 
There is a way for a HomeKit controller (iOS, Apple TV, etc.) to give access to other controllers (i.e. our gateway), but that process is undocumented, so I had no idea how to implement it.