Showing 2nd Level Parent Only

I am currently having some issues getting the wp_list_pages to work how I would like it to.

<ul id="the-section-title">
<?php wp_list_pages('title_li=&include='.$post->post_parent ) ?>

My file structure is Home -> About us -> Subpages. What I would like to happen is somewhat of a breadcrumb style navigation with the title “About us” showing up on the subpages. Problem is when you are on the About us page, you see the entire navigation (Home -> About us -> Subpages). I am assuming the reasoning behind this is because it is showing you the parent of About us which is Home.

So how do I tell wordpress to only show the parent title to a page two levels down?

Thanks