random fire, and a group action

I'd like the enemy to be able to have 1/200 chance or something of firing

And if the enemy hits the wall, I want the whole group to go down, not just one of them.

How do I do this?

Your questions aren't really very clear, but this might help you:

• give the enemy a variable shootingchance

for each enemy

-enemy set shootingchance : floor(random(201))

subevent:

enemy compare variable shootingchance = 200

-enemy shoot

if enemy hits wall

pick all enemies - perform action.

Thank you for your help.

The movement itself kind of worked, with fewer enemies.

To be less confusing, I'm simply making a space invaders game. And my goal is to make them move down their traditional way, and firing their traditional way too.