How to Generate Multiple Menus

On some pages of my site, I would like to display a 2nd “sub-menu”, if you will, under the main menu.

I have added a custom field to all my pages to separate the “main” from the “top” menus/pages. I still need to use WP’s sort order. So I’ve tried hacking the following line of PHP code:

<?php wp_list_pages(‘title_li=&sort_column=menu_order=&meta_key=Menu&meta_value=Top’); ?>

But it doesn’t display anything at all. Is my syntax right? Can I ask it to do two things at once — sorting by menu order only those pages with the custom Menu field of “top”?

Thanks,
Jane