From my experience with the newest versions of boat's assets..
Place your gates, stoppers etc. Connect them all with an invisible track.
Use this track object <kuid2:76656:500041:7> ATLS Controller/Slave TRS19
Place it on the invisible track in the middle. The controller will see only 3 objects on the invisible track on each side max.
To trigger more assets like traffic lights or multiple gates, connect the invisible track to them and then add this track object to one end of the track
<kuid2:76656:500040:4> ATLS Slave Trigger TRS19. This will run the length of the track and trigger the extra assets.
Now you can place triggers on different tracks to get 2 or more different tracks to set it all off.