Different primary links on different sites.

Hey everybody
I'm just creating a Drupal site. As main-navbar I use a css block with different items. Now what I want to do is to attribute different primary links as subnavebars to certain items of the css block.

For example:
I have a item called home in the css nave-bar.
Now I want some sub items like blog, start..... using primary links.

I have an other item in the css block called about us.
And I want sub items like history, members....

Could you give me adive?

Please

Thanks in advance