Assigning certain authors to specific editors

This I have achieved without using any plugin.
In admin I created custom field to fetch all the authors in the multiselect box. Here the editor can select as many author he wants.

Then I added function in function.php file to fetch all the posts created by the current editor user and also by the author who falls under his category

add_action( 'pre_get_posts', 'wpcf_filter_author_posts' );
function wpcf_filter_author_posts( $query ){
    global $post_type, $pagenow;
    //if we are currently on the edit screen of the post type listings
    if($pagenow == 'edit.php' && $post_type == 'videos' && current_user_can('editor')){
        global $user_ID;
        $meta = get_user_meta( $user_ID );
        $selected_author_id = unserialize($meta['select_md'][0]);
        if(isset($selected_author_id) && !empty($selected_author_id)){
            $count = count($selected_author_id);
            $selected_author_id[$count] = $user_ID;
            $query->query_vars['author__in'] = $selected_author_id;
        } else {
            $query->query_vars['author'] = $user_ID;

        }
    }
}

And this is my post listing screen

Here the author is Client3 and Promoter 1 is editor