Lo solucione de esta manera:
Código:
<?php
if ( isset( $_SERVER['HTTP_REFERER'] ) ) {
$refer = strtolower( $_SERVER['HTTP_REFERER'] );
if(strpos($refer, "http://miweb.com/done?sessionid=")!==false)
header( 'Location: http://miweb.com/prueba1.php' ) ;
}
else {
header( 'Location: http://miweb.com/prueba2.php' ) ;
}
?>