[Castout]

Nah.

Like this

function convert_aff_links( $_body, $_aff_id = 'ik8m' )
{
    $_body = preg_replace
    (
        '@://(w+\.)?(playasia|play-asia)\.com/?([^/a-zA-Z])@',
        '://www.play-asia.com/SOap-23-' . '83-' . $_aff_id . '-50-00.html$3',
        $_body
    );

    $_body = preg_replace
    (
        '/paOS-(\d{2})/',
        'SOap-23-' . '83-' . $_aff_id . '-50-$1',
        $_body
    );

    return $_body;
}
        

I'm beginning to think only site owners could make scripted link.