large 4th & 6th order bandpass enclosures

[SICKSPD]

So I have a basic understanding of these types of enclosures as to how they are laid out and their functionality, but as I've noticed with large bandpass enclosures (especially 4th orders) that have like 6 15s with 3 woofers mounted on opposite sides with a large tunnel acting as a port, couldn't this simply be considered two separate but large sealed boxes that just have occupy a joined area? With smaller bandpasses theres a distinct vent coming from the ported section of the box but with these really large bandpass setups it seems more like two giant sealed enclosures facing one another recessed within a cavity.

Basically if I had an ordinary square sealed box and the edges of the sides extended out a couple of feet this could be considered a 4th order? The tuning might be horrendous but it still fits the guidelines of having one sealed enclosure with a ported space outside that… thats how Im viewing these walled 4th orders. Can someone clarify my understanding a bit?