Not lose a life for every ball when multiball is active?

I have a breakout style game where a powerup creates an additional ball. However, at the moment every ball that crosses the line costs 1 life but I only want the life counter to go down when the final ball leaves the screen.
This is the life logic:

Don’t put the decrease life action in the event in your screen snip. Add a subevent to it which checks if the number of Ball instances in the scene is 0,and decrease life by 1 if so: