Add an additional wrapper around your posts in the Genesis framework

functions.php

<?php
//* Do NOT include the opening php tag

add_action( 'genesis_before_loop', 'jh_open_wrapper' );
add_action( 'genesis_after_loop', 'jh_close_wrapper' );

function jh_open_wrapper() { ?>
<div id="jh_posts">
<?php }

function jh_close_wrapper() { ?>
</div><!-- /#jh_posts -->
<?php }