group-posts-by-terms.php

<?php 
/**
* Get posts and group by taxonomy terms.
* @param string $posts Post type to get.
* @param string $terms Taxonomy to group by.
* @param integer $count How many post to show per taxonomy term.
*/
function list_posts_by_term( $posts, $terms, $count = -1 ) {
$tax_terms = get_terms( $terms, 'orderby=name');
foreach ( $tax_terms as $term ) {
echo '<h2>' . $term->name . '</h2> <ul>';

    $args = array(
    'posts_per_page' => $count,
     $terms => $term->slug,
    'post_type' => $posts,
     );
    $tax_terms_posts = get_posts( $args );
    foreach ( $tax_terms_posts as $post ) {
        echo '<li><a href="' . get_permalink( $post->ID ) . '">' . $post->post_title . '</a></li>';
    }
echo '</ul>';
}
wp_reset_postdata();
}