Next and Previous post link from the same subcategory

How i can make Next and Previous post link from the same subcategory even if the post has multiple categories.

I do read all “wp Codex” like http://codex.wordpress.org/Function_Reference/next_post_link …
and i do search a lot but there is no answer.

My site is http://wallpaperevo.com

Here is my categories build

Wallpapers
-Cars Wallpapaers
–Audi Wallpapers
–BMW Wallpapers
–more..

I just want to navigate between all the posts from the same subcategory for example in “BMW Wallpapers”.