in c2, you could create a variable outside of 'bullet' that is changed by 'bullet'.
background.bullet_hit_sprite2 (boolean set to false at start up)
event: bullet collides with sprite2 >
action...set background.bullet_hit_sprite2 to 'true'
event: bullet (object) > if background.bullet_hit_sprite2 = 'true' >
i think this will work. it should help you get around 'picking' for now.
hope it helps...