There is a way. Just redirect the page to base url once the utm_expid=67183125-2
is got. ie,
if($_GET['utm_expid']) { //header to redirect to myweb.com }
Its a tricky way. Hope you are permitted to use it.
Just start a session and store value in session variable. you can regain it even page is re directed.
ie
<?php
session_start();
if($_GET['utm_expid']) {
$_SESSION['variable_name']=$_GET['utm_expid']
//header to redirect to myweb.com
}
?>