Browsing Into Levels

Hi, I been wondering the best way to make the level browsing, I mean, those links up in page which tell you the position you are, and make you able to return sections back, keeping some kind of logic of where you are. I been used the url vars to do this but I arrive some point where there are coincidences and it loose sense, it jumps to other section, where indeed have to, but not where it logically should. any suggestions? thank :)