Prefab & If Statement

So I have a prefab called "Wood"

Now with this prefab, I want it to be, So if any part of it falls to a object called "Empty23" I want it to do the if statement.

I got it doing the if statement, But there's a couple problems
When It works, It's just one item that I told it to go like "Only do the 'if statement' if Layer5Front gets to Empty23"

I don't want this, I want it so it's anything within the "Wood" Prefab.

I am sorry if I am a noob, I don't even know if this is possible.

Thanks in advance.