Hello there DDM9,
Welcome to Apple Support Communities. You can find some guidance to help with this per the Apple Support article: Set up security cameras in Home on iPhone - Apple Support
"Create Activity Zones for HomeKit Secure Video cameras
You can create zones that focus your HomeKit Secure Video camera on the most important areas within its view—your front walkway but not the sidewalk behind it, for example. You can then be alerted when motion is detected in these zones.
Note: You can create Activity Zones only for cameras set up to record when a specific motion is detected. Activity Zones don’t affect motion detection automations.
- On the Home tab, tap the camera tile, then tap .
- Tap Select Activity Zones, tap the video to create a zone, then tap Add Zone.
- To have your camera detect motion only outside the zone you defined, tap Invert Zone.
- Create any additional zones you want within the camera’s view—one for the driveway and another for the mailbox, for example.
- Tap Done.
To remove an activity zone, tap Select Activity Zones, tap inside a zone, then tap Clear."
Should you need additional assistance, get in touch with Apple Support:
Apple Support
Best regards!