Nav Menu on Posts page

I am using WP more as a CMS, then as a blog. I have added a bunch of pages, and under:
Settings
Reading
Front page displays:
– Front page: [I selected my “home” page]
– Posts page: [I selected my “Announcements” page]

My header.php calls a list_secondary_nav() function in my function.php.

function list_secondary_nav($return = 0) {
global $wpdb, $post;
$current_page = $post->ID;
// Note: $current_page is the ID of the latest Post (not the Announcements page
while($current_page) {
$page_query = $wpdb->get_row(“SELECT ID, post_title, post_parent FROM $wpdb->posts WHERE ID = ‘$current_page'”);
$current_page = $page_query->post_parent;
}
$parent_id = $page_query->ID;
$parent_title = $page_query->post_title;
if($wpdb->get_results(“SELECT * FROM $wpdb->posts WHERE post_parent = ‘$parent_id’ and post_type = ‘page’ AND post_status = ‘publish’ “)) {
echo'<ul id=”navSec” class=”group”>’;
$html = wp_list_pages(“child_of=$parent_id&depth=$depth&echo=”.(!$return).”&title_li=0&sort_column=menu_order”);
echo”;
}
if($return) {
return $html;
} else {
echo $html;
}
}

The issue is when I click the Announcements link in the secondary Nav menu, the page I end up on (index.php I think) does not show the secondary Nav.

What I want is that the page specified in Settings | Reading | Front page displays | Posts page, will display all the posts (like index.php), but show the navigation as though it is the page.

Is this possible?

Note: I tried creating an “Announcements” template which would get all the posts, but it doesn’t appear a page can get the posts.

Thanks,
Josh