How do I make structure pass through layout

I'm making a shoot em up, think R Type or Gradius. I want my player to pass through a structure, and get battered as they pass, but I cant figure out how to bring the objects of the structure through the layout. I'm sure It's pretty straight forward but can't remember it. Think I tried it before.

H

you mean like with line of sight maybe? When player is near like guns have the guns spawn bullets and shoot at the player... or maybe spawn objects when it's in line of sight of an object. Not sure if that's what you're looking for lol

Thanks for you reply but I dont think I got across what i'm trying to do. I want to bring in some land in my space game and other objects at the same time. For example, if I wanted to bring in 20 satelites in different positions on the layout (they would then move through the layout with bullett behaviour).

H