Never heard of this feature in any vehicle before, sorry. Most systems will provide air to all the duct work, but use valving in order to adjust temp. You can either sync with the pass or not, but no way to completely turn off, aside from what you said and turn the vents off at the vent.
2013 RAM 1500 Laramie Longhorn - Black Gold Pearl with all the trimmings. HEMI, 3.92, 8-Speed and Air Suspension
14" Magnaflow, BAK FiberMax Tonneau, Misc Whelen Emergency Lights and Switchpak, 275/60R20 - BFG T/A KO2