Randomized NPC placement possible?

Let's say I make a custom NPC Pirate, Human Male as a base. How difficult would it be to have a checkbox option to randomize appearance on placement? Like, every time I drag the custom NPC from the list to place it in the game world it would give it a random race/gender/appearance.

I think that would help with making more immersive game play than having 15 of the same identical NPCs or at least make less work for a GM planning a game not to have to create a vast variation of NPCs.