You would need to check if any Dice have val=1 AND any Dice have val=2 etc until 5. And since it's a chore to do that with each Dice you can put the Dice objects into a Family, this limits events so you can group all Dice together.
Then you can say for each Dice (family) where Dice.val=1 set variable to Dice.pickedcount. Same as before basically but with a Family. Then if it's 1 or greater then you are good. You could check for val=1,2,3,4,5 in the same event with subsequent sub event checks and if all of them return 1 or greater then you have the straight.