That entire climate control is one unit, from what I can gather online. Maybe find a used one from a wrecker and mess around with taking it apart to see if there is some physical piece that can be altered or removed. Heck, it might even be possible to do this by just pulling the knob off and seeing if there is an extra electrical contact at that point in the rotation.It is the three dials with the centers as push buttons. When the temp is turned to lowest dial setting, it turns on max AC which is AC plus recirc.
Yeah, it is probably not a simple hack-around. Someday.... someday...
I would be a bit more cautious with doing this type of mod on newer cars with such integrated wiring systems. I got lucky that Toyota made my idiot-proofing idiot proof for idiots like me who want to tinker with idiot-proofing. It's like idiot inception over here. LOL