`
<?php
/**
* Plugin Name: Display Posts to Posts 

// Create the shortcode
add_shortcode(‘p2p’, ‘display_post2post’);

function display_post2post($atts) {

extract( shortcode_atts( array(
‘relation_post’ =>  ”,  //posts_to_pages or relationship targeted
                        // other attributes to pass?
), $atts ) );

$args = array(
‘relation_post’ => $connected_type,
‘connected_type’ => $connected_type,
‘connected_items’ => get_queried_object_id(),
‘nopaging’ => true,
// other filters ?
);

$return = ";
$connected = new WP_Query($args);
if ( $connected->have_posts() ):
$return .= "<h3>Related posts:</h3>;
$return .= "
<ul>";
while ( $connected->have_posts() ): $connected->the_post();
$return .= "
<li><a>"><?php the_title(); ?></a></li>
";
endwhile;
$return .= "</ul>
";

// Prevent weirdness
wp_reset_postdata();
$return .= ”;
endif; wp_reset_query();

if (!empty($return)) return $return;
}
?>
`