Several peoples Apple TV in one HomeKit

Why does the home owners iCloud-account need to be so intertwined to an Apple TV to make it appear in HomeKit? What i mean by intertwined is that the same account used for HomeKit is also the same account used for iCloud pictures, couldn't there be two different log-ons for each?

E.g. My father owns the HomeKit, we both have Apple TV's. I want to be able to see my Apple TV in our HomeKit and not see his iCloud pictures. I know i can turn the pictures off, but still, i want my pictures on my Apple TV.