How to Filtering String Base on a Specific Criteria on PHP

I'm very newbie in PHP and I have a problem in filtering a value. Here my case :

• when I call data $origin from a database the result is a country code, example: US, GB, AU, BR, PT, or MX
• then, I want to filter them example: if the code is between US, GB, AU = EN, if the code is between BR, PT, MX = PT, and if the code is beside US, GB, AU, BR, PT, MX = INT, and if there is an error when calling data $origin = ERROR

I already search the solution but not of them is solving the problem as I'd expected. Here some of the code :

$origin = 'AU';
$geo = array('US', 'AU', 'UK');
foreach ($geo as $result) {
    //if (strstr($string, $url)) { // mine version
    if (strpos($origin, $result) !== FALSE) { // Yoshi version
        echo "EN";
        return true;
    }
}
echo "INT";
return false;

and

$origin =  'BR';

if (strpos($origin,'US') !== false) { //first we check if the url contains the string 'en-us'
    $result = str_replace('US', 'EN', $origin); }
    else {
        $result = str_replace('BR', 'PT', $origin);
      }

echo $result

I want to filter based on my cased and I want the result can call by using echo $result

Thanks