Spawning actors only on the outer region of a box

by the “is point in Box” query, only actors are spawned that are between the two boxes… which is what I want. The problem is that I have no control over how many are spawned between them.

What I actually want to do. In my sound system, sometimes random sounds are dropped around the player to give the scene more life. Since everything takes place in buildings, the sounds have to “come out of the walls” and not in random positions around the player. I should have written all this in advance ^^

That’s why I need to control exactly what and when I’m spawning on the surface of a box that I use as a reference.