Verifying Hostname

[scrypte]

Ok I am writing a CMS that can be used on multiple sites with one back end right now. I am working on my function to verify and get the hostname from the URL. Some of our domains though look like any of these:

www.domain.com
domain.com
sb78392kjnds.members.domain.com <-- with newton for members areas
members.domain.com

the one with the newton always starts with sb followed by 9 numbers and letters

Here is my function I am using to extract the hostname better.

function get_hostname($hostname) {

// Check the url for a newton
$find_newton = preg_match('^(sb[A-z0-9]{9})^', $hostname);

// If the newton exists cut it and recreate url
if ($find_newton == 1) {
	$true_host =  preg_replace('^(sb[A-z0-9]{9})\.+|members.|^', '', $hostname);
} else {
	$find_www_host = preg_match('|www.|', $hostname);
	$find_members_host = preg_match('|members.|', $hostname);

	if ($find_www_host==1) {
		$true_host =  preg_replace('|www.|', '', $hostname);
	} else if ($find_members_host==1) {
		$true_host =  preg_replace('|members.|', '', $hostname);
	} else {
		$true_host = $hostname;
	}
}

echo  $true_host;

}

is there a better way to do this? If so please point me in the correct direction

[mjax]

function get_hostname($hostname) {
	return implode('.', array_slice(explode('.', $hostname), -2));
}