[Scripting Question] [16.2] Ability that may hit twice.

Im working on a more complicated ability idea, each move (Depending on stab or not) has a chance to either hit twice or hit with stab damage (if not stab) planning to be 1/3 chance for stab damage then a 1/3 chance for double hitting (cant get both) leaving a 1/3 chance for nothing to happen.

i can do all the coding for stab or not, and the stab damage, its the part about hitting twice thats hard. i have tried basing on parentalbond and i know thats the way but im not sure how to do the chance check first (So the 2/3 of it not hitting twice and 1/3 it hitting twice) first or where the check after that would go to active the double hit.

any help will be great, just stuck with this tiny bit.