You got what I was trying to say. I might of confused everyone with the descriptions and stuff, BUT you got it!
BASICALLY: A wall like the Gravity Wall that allows Particles -> combined with -> a wall like Wall which will block pressure using just 1 wall instead of 8. this will allow 16 particles to occupy one complete wall or a 4x4 space.
I think you all know where I'm getting at now.
BTW: Instead of calling it a Pressure Wall, it can be called a Particle Wall. (I've noticed that most walls are named after the things that they allow to pass through them.) XD