Check to see if more than one post

by

Try this to get the count of posts:

<?php

 $connected = new WP_Query( array(
  'connected_type' => 'posts_to_pages',
  'connected_items' => get_queried_object(),
  'nopaging' => true,
) );

echo "<h2>Found: $connected->found_posts</h2>";

?>

You could write a variable like:

$the_count = $connected->found_posts;

Then test with an if

if ( ( $connected->have_posts() ) && ( $the_count > 1 ) ) :