This is a new logic script that entails a combination of per-person (or per-scene) memory and a requirement that all of a set of conditions be met before some behavior you define gets executed. This is a fairly powerful game mechanics tool. You could, for example, require each of your visitors to go to several places in your scene before they can use a teleporter to go somewhere else. Or only open a door when three spell ingredients (keys) get put in place (locks), regardless of who places them.
New Reflex script: And gate