This is something I have been researching recently. I want a hitch for a different purpose, however, the answer I have gotten from CW and another RV dealer is - as long as it attached the chassis frame of the trailer there should be no problem.
The larger issue is 1) Is double pull allowed in your area? (I am guessing it is), and 2) Will the total length of the truck, 5er and trailer be less than the maximum length allowed in your area?
2013 Infinity 3640RL with Trailair pin box
2008 F-250 King Ranch Power Stroke diesel with B&W Companion Slider hitch