Example that shows how to add some headings between ticket selector rows. Requires WordPress + Event Espresso 4.

ticket_headings.php

<?php
//* Please do NOT include the opening php tag, except of course if you're starting with a blank file

add_action( 'wp_enqueue_scripts', 'my_ee_add_ticket_row_headings', 11 );
function my_ee_add_ticket_row_headings() {
  wp_add_inline_script( 
    'ticket_selector',
    'jQuery( document ).ready(function($) {
      $(".ee-ticket-tees-for-keys-golf-tournament-executive-sponsor")
      .before( "<tr><td colspan=\'3\'><h3>Tees For Keys</h3></td></tr>" );
      $(".ee-ticket-home-build-sponsorship-home-partner")
      .before( "<tr><td colspan=\'3\'><h3>Home Build Sponsorships</h3></td></tr>" );
    } );'
  );
}