Limit to 1 Weapon Proficiency for Assassin

Hi All,

The Fighter>Devoted subclass can select only 1 weapon proficiency at creation. 

I want to apply the same restriction to the Rogue>Assassin subclass as well for roleplaying reasons. However, I can't seem to find the code in the game's files that enforces this limit of just 1 proficiency. 

I can find the code that controls weapon proficiencies for all characters as you level up in the Global gamedatabundle, but I don't want to limit all of my companions to only one proficiency. Only my assassin. 

Can anyone help me find the code I need to add to make my customizations?

Thanks a lot in advance!