From what I understand, you're trying to create a random object when your brick is destroyed. Instead of having differet objects for each of your "powerups", put them all in one object as different animations. Then, have an event:
- Brick On Destroyed
- > Brick Spawn Powerup
- > Powerup Set Animation to choose("anim1", "anim2", "anim3")
Then for collecting the powerups its a simple change to
|- If Powerup Animation == "anim1"
-> Do Powerup1 stuff
|- If Powerup Animation == "anim2"
-> Do Powerup2 stuff