Computer Hope

I found another post on this forum that was very useful about banning IP in a PHP file.
I will attach the code below.
I do have a question about this code.
I am using IP Ranges in the ban.txt file.
Sometimes when doing this there is one IP within that range that is a user that does not need to be banned.
How can I add another text file of set it up in the PHP file to allowed IPs and have it override the ban.txt file?
Is this possible?
<?php
$userIp = $_SERVER['REMOTE_ADDR'];
$ips = file('/ban.txt');
$isBanned = false;

foreach($ips as $ip) {
   $split = explode(',', $ip);

   if($split[0] == $userIp)
      $isBanned = true;
      break;
}

if(!$isBanned) {
  echo "It seems you have been banned from viewing this website.";
  echo "
";
  echo "If you think you have been banned in error please contact me.";
  exit();
}
?>