I think this wont be very useful, when you post something in Honda it is a Car so when people will browse the "Cars" category they will see Honda in there, otherwise your category "Cars" will be always empty.
One category per post is the basic feature of the plugin, disable multiple choice in settings and you will be able to chose only one category.
So if you choose Honda the post will appear only in Honda category.
I understand that you want to see that your post is in "Honda" car and not motorcycle without checking the whole list, to see the list as in "Multiple choice" but only the last selected category applied. That is a personnalized feature, I'll think about it.