Sort and Group Posts by Custom Field with Unique Headings in

<?php
    $args = array(
        'post_type' => 'branch',
        'numberposts' => -1,
        'order' => 'ASC',
        'orderby' => 'meta_value',
        'meta_key' => 'state',
    );

    $branch_posts = get_posts($args);
    foreach($branch_posts as $post) :
    setup_postdata( $post );

?>

    <?php
        // Only show posts with the 'State' custom field
        if (get_field('state')) {

            // Set the state of this post
            $current_state = get_field('state');

            // If this post doesn't have the same 'State' as the last one, let's give this one a heading and open the <ul>
            if ($current_state != $previous_state) {

            // $previous_state isn't set until the end of this foreach, so the first one doesn't have this variable
            // If this isn't the first list, close the last list's <ul>
            if ($previous_state) { echo '</ul>'; }
        ?>

            <h1><strong><?php echo $current_state; ?></strong></h1>
            <ul>

        <?php } ?>

                <li><a href="<?php the_permalink() ?>"><?php the_title(); ?></a></li>

        <?php
            // Remember, we closed the <ul> before the <li>'s, clever huh?

            // Set the 'State' of the this post, to compare to the next post
            $previous_state = get_field('state');
    } ?>
<?php endforeach; wp_reset_postdata(); ?>
</ul>