Map or Edit Query String Values in Views?
You can use the hook_views_pre_view function in your custom module to change the query parameters using PHP, so a rough untested example of the code could look something like:

function MODULE_views_pre_view(&amp;$view) {
  switch ($view-&gt;name) {
    case 'YOUR_VIEW_NAME': {
      // change your query strings to
      if ($_GET['value']) {
        $value = $_GET['value'];
        $new_value = substr($value, 0 , 6); // remove the 'value%' from Site A querystring
        $_GET['value'] = $new_value;
      }
      break;
    }
  }
}