Trouble Understanding "Emerald Check - Once" Linedef Executor 339

[Spherix]

Hi everyone, I'm making a test map to familiarize myself with Zone Builder. I started with the first 5 videos in SeventhSentinel's tutorial series, saving the last one for if and when I decide to do more complicated things with slopes. Currently I'm trying to make a door that opens when a button is pressed, which is simple enough, however I'd like the button to only activate if the player has the green Chaos Emerald, and this linedef executor does not appear to have any documentation. I have been able to make this linedef executor work with the default requirement of all seven Emeralds, is there a way for it to only require a specific one/few?

Thanks in advance.