Contacted Infinity. They said, that is not on your car. duh. I ask why not? What kind of an option would be necessary to have that switch? Was standard on my Enclave. No answer back from them. Very disappointed with Infinity.
Well not only does my car not have this feature but according to the dealer it cannot be added. This feature was discontinued with the 2018 model. Anyway to contact Infinity direct and complain about this? Won't help my car but this just looks like a way the cut a $50 part out of a $58,000 vehicle so they could say a few bucks.
QX60 used to have that switch. It got eliminated in 16 or 17 - I don't recall which year.
If I had to guess why, I'd say its because too many stupid people would complain their tailgate was broken because they'd inadvertently switched the switch. I used to tell every single customer what it was for and some of them still called me wondering why their tailgate wouldn't open.
To the original post - I'm sorry, but I don't know any way to accomplish what you want. The good news is if the gate gets much resistance on its way up, it will stop and go back down (try it - stop it with your hand on its way up and see what happens).