With Smart Lighting, signal only travels from the Bridge to the specified Smart Light, and does not jump from Smart Light to Smart Light. The good news is that the command to trigger will jump from device to device as long as they are in a group.
For example, your gate may be too far from the Bridge for your application to control that Smart Light, but if Path Lights are on the way from the Bridge to the gate and are in a Light Group with the Smart Light on your gate, then lights will trigger each other as intended. Keep in mind that it is best practice to keep these devices within reasonable range as operation is much more consistent this way.
Your next best bet may be one of our Spotlight or Floodlight Cameras. However, given the distance, this option might also require an extender that is rated for outdoor use as you’ll need one half way between your gate and your router, along with very efficient Wifi.
Please let us know of any other questions!