Could anyone assist me. I have two directories in the root.

/online
/residential

I am trying to have a different top nav for each page. So if I want to show the nav for /residential i use the path /Residential/% which works fine. The pages within that directory show up fine in the nav. If I make a third level directory, how to i get that to be hidden in the main nav? I wanted this third level navigation to be shown elsewhere.