Not turn off accessories, but switch to another scene?

I have a Toilet room with a Hue color light and motion detector in the ceiling and a Hue color light outside the door. The outside light indicates occupancy—green for unoccupied, red for occupied. Easy to see from a distance and prevents people from opening the door and finding the toilet occupied. After five minutes of no motion (the person has left), the motion detector turns off the ceiling light and turns the outside light from red to green.

At least that's how it worked in the Philips Hue app. Now that I've moved everything over to HomeKit, I see no way of setting different colors for that outside light. Using an automation, I can turn the accessories associated with the motion detector either on or off, but I can't simply change scenes. Moreover, I can't use a "When motion is NOT detected" automation because it activates immediately, even if the "When motion IS detected" automation is currently active (set for 10 minutes), leaving the person inside in the dark.

Two possible solutions. The preferred solution is to set a time before the "When motion is NOT detected" automation is activated (When motion is not detected for 5 minutes, set to the scene "Unoccupied". But that isn't an option in HomeKit.

The second possible solution is, "When motion is detected", set the scene to Occupied, then when no motion is detected for 10 minutes, set to the scene "Unoccupied". But again, that isn't an option.

So I'm looking for a third solution. How can I have Homekit detect motion in a room and set a specified scene. Then, when motion is not detected for a specified time, set another scene. Any ideas anyone? I really don't want to revert to the Hue app just for this one room.