Easy way to set menu based on path?

I'm not sure I have a good grasp of different ways to deliver a menu on the page, or to grab a menu under some part of the tree. Is there any reason the code below isn't working? Menutrails works well great for node-types now; I'd like an easy way to use the functionality for other cases.

Eg

if(in_array('employment', array($_SERVER['REQUEST_URI'], strtolower($node->field_sidebar_title[0]['value'])) 
{
    $item = menu_get_item();
    $item['href'] = 'employment'; #or node/179?
    menu_set_item(NULL, $item);
}

Thanks for any pointers.