LP gas connections

these sure look like the can be separated, call em
[url]http://www.regoproducts.com/lpg/lpg-nh3-products/products/7525b.html[url]


there is always mbsturgis
https://mbsturgis.com/rv-propane-hoses-sturgi-stays-quick-disconnects-regulators/two-stage-automatic-changeover-regulator.html

The only way to do it is to purchase two adjustable high pressure regulators (10 psi outlet) and set one 2 psi lower. The higher pressure would be the dominant one until the tank pressure dropped to the second regulators' outlet pressure then the secondary tank takes over. The only thing you would not know is when the change over takes place, as there is now indicator other than installing a pressure gauge on the dominant regulator and monitoring its' output.