post-page: reference to parent page?

You can do that:

//add reff to query vars to hold the referring page ID
add_filter('query_vars', 'my_query_vars');

function my_query_vars($vars) {
    // add movies_view to the valid list of variables
    $new_vars = array('reff');
    $vars = $new_vars + $vars;
    return $vars;
}

then add ?reff=<?php echo $post->ID; ?> to your “post’s detail” link

and on your “post-detail.php” you can create a back link using that query var

<a href="https://wordpress.stackexchange.com/questions/11575/<?php echo get_permalink(get_query_var("reff')); ?>">Go Back</a>

and as for having several post-pages take a look at:

How to quickly switch custom post type singular template