Quick and dirty, wouldn't recommend using it exactly, just an example to help you out, in php.
in your new found iframeless include area do something like this
PHP Code:
<?php if($_GET['sect'] =='something') include('yourpage.php'); else include('anotherpage.php'); ?>
Then just call somepage.php?sect=something and it will replace whatever is in anotherpage.php on somepage.php to yourpage.php on somepage.php