Vertically combine Launchpad and APC40 session view boxes?

[stethoscanomaly]

I want my Launchpad and APC40 to share one 8(horizontal) x 13(vertical) selection box in session view instead of each having it's own box.

I know it's possible to run two APC40s (or a 40 and a 20) either with independent selection boxes (how my Launchpad and APC are running now) or with a horizontally combined 16x5 box. I got a script from somewhere allowing me to combine the boxes in this way, and it worked without any issues, so I at least know this kind of thing is possible.

Does anyone know how I might be able to run my Launchpad and APC40 with a shared 8x13 selection box with the Launchpad as the top 8x8 and the APC as the bottom 5x8?

Thanks in advance for any replies