How do I disable touch on an object?

I'm making a game where the user can basically press a sprite called "YES" or a sprite called "NO".

Once they tap either "YES" or "NO", both are grayed out (via animation), and I want it so you can't tap on YES or NO again.

I put them both in a group and set the group to Deactivated when either is tapped, is this the best way?

create a variable (for example: isTouched) as a global variable.

Once one of them is 'Touched' the variable will be "1".

On the Touch-event add another condition wich will check if the variable is not "1"(or just equals "0").