If custom field X show wp_list_bookmarks id Y

I’m trying to make a page template that allows me to add a custom field with a ID-number pointing to a link category and then display that link category on the page.

This did not work:

<ul>
<?php wp_list_bookmarks('category=<?php $key="Linklist"; echo get_post_meta($post->ID, $key, true); ?>&show_description=1&title_before=<h3>&title_after=</h3>'); ?>
</ul>

Any suggestions?
Would be great if the script supported multiple instances of wp_list_bookmarks and Linklist custom field.