HomeKit Room Based Access Control I am considering adding HomeKit devices to a few rooms in a house, and assuming the HomeKit Home is shared with the family, that presents an issue with access.

It would be best not to allow everyone to control every device. For example, would it be possible to configure the Home to that John and Jane can both control living room devices, but only John can control the lights in his office? Thanks!
Nope. No fine-grained control of access in HomeKit at this point.