How can I get my CSS navigation tabs to work for groups of similar pages?

I'm adding navigation tabs to the top and I have a different css class to indicate the current tab, inactive tabs, etc.

My question is the following is there an easy way to tell which "group" should be highlighted by the page url?

For example, if the user is on the page

/index.php?main_page=account

I will want to have the "My Account" tab highlighted as the active tab.

Also for the pages:
/index.php?main_page=account_edit
/index.php?main_page=address_book
/index.php?main_page=account_password
/index.php?main_page=account_notifications

The breadcrumb correctly identifies these pages as belonging under the My Account page.

How can I get the same info for the active tab?