Hello ilim,
To my knowledge, Scenes don't work by setting custom locations for them to run in. You just add a name, icon, and Accessories they affect. The Rooms in your Apple Home have what is know as Zones.
- Basement
- Main Level
- Outside
- Second Level
These are the default ones, but you can create your own too! This allows you to say "Hey Siri, turn on all the lights on the second level." Rooms can belong to multiple Zones.
- Open Home
- Tap More (three dots in the upper right)
- Tap on on of your Rooms
- Tap on More (three dots in the upper right) again
- Tap on Room Settings
- Tap on Zone
This will allow you to change the zones and use them when talking to Siri.
If you wanted to use Scenes, you could create a new scene called "Hallway Lights On" that would turn all the hallway lights upstairs on.
- Tap the plus icon
- Tap Add Scene
- Set a Scene Name and Icon
- Select all the hallway light accessories upstairs.
You can always edit Scenes, by long tapping on the Scene and tapping on Edit Scene.
Is this what you were looking for? Classifying Rooms as Zones? All Accessories within a Room would also belong to that Zone. As stated above you create as many Zones as you want and Rooms can belong to multiple. You could have a "Main Bedroom" and "Upstairs" Zones. If you asked Siri to turn all lights on Upstairs, Main Bedroom lights would also turn on. You could also say turn on the Main Bedroom lights and only these lights would turn on.