Only able to use item of type once?

I have two main heroes in my map, so I want to place 2 of each power up tome, but I want to limit one per hero so each hero can aquire 1 of each.

Is this at all possible?

Theres two ways I know how to do it. The second way is only experiemental as I have never tried it.

1) Catch when an item is picked up with the appropriate event.
Since it is a tome, check if that hero has already used it (save it in a
variable) and if he has, create another tome of the same type on the
groound and "de-buff" the effects of the tome the hero picked up.

2) Catch when a unit is issued a smart order on an item. If the item being targetted is of that tome type, check if the hero has already used it and if he has, pause him, order him to stop, unpause him.