> How about, accept 3 digit pages starting with 500
> and all 4 digit ones:
> -*
> +*xyz.com/showthread.php?t=123456&page=*[5-9]*[0-9]*
> [0-9]
> +*xyz.com/showthread.php?t=123456&page=*[0-9]*[5-9]*
> [0-9]*[0-9]

Hmm... ok, I'll try that and see how it works. Thanks.