Limit BuddyPress Messages to users of same rank

add_action( 'messages_message_before_save', 'mycred_pro_intercept_bp_message' );
function mycred_pro_intercept_bp_message( $message ) {

    // We need recipients and myCRED
    if ( empty( $message->recipients ) || ! function_exists( 'mycred_get_users_rank' ) ) return;

    // The message sender
    $cui = bp_loggedin_user_id();

    // Get the senders Rank ID so we can get the ranks minimum balance requirement
    $senders_rank_id = mycred_get_users_rank( $cui, 'ID' );
    $senders_min = get_post_meta( $senders_rank_id, 'mycred_rank_min', true );

    // Now we loop through the recipients
    $good_recipients = array();
    foreach ( $message->recipients as $recipient ) {

        // Get the recipients rank ID so we can get the rank minimum balance requirement
        $recipients_rank_id = mycred_get_users_rank( $recipient->user_id, 'ID' );
        $recipients_min = get_post_meta( $recipients_rank_id, 'mycred_rank_min', true );

        // If recipient is on a higher rank, continue to the next
        if ( $recipients_min > $senders_min ) continue;

        // Add recipient to the "good" list
        $good_recipients[] = $recipient;

    }

    // Replace set recipients with the ones we have approved
    // If this results in an empty array (all recipients declined)
    // BuddyPress will show an error to the user and no message is sent.
    $message->recipients = $good_recipients;

}