Smarty reading config values from .conf files in PHP -

for meeting schedule, want have dynamic pages given room. user can edit file named "schedules.conf" in config folder. @ moment looks this:

[rooms] room = 5022 room = 5082 

and can load , shows 2 links in web page:

{config_load file="schedules.conf" section="rooms"} ...... ...... ......  {foreach from=#room# item=r}  <li><span><span><a href="{$smarty.const.site_url}/admin/schedules.list.php?room={$r}">schedules {$r}</a></span></span></li>                      {/foreach} 

so links handler php file, in php file want check weather room exist in config file, if manually change value room in address bar have chance handle that:

  if(!isset($_get["room"]))   {       header('location: '.site_url.'/admin/index.php');   }   else   {       $validrooms = $smarty->getconfigdir();        //how check id $_get["room"] value exist in config file         } 

grep page conditional checks using smarty isset()

edit

in light of comment #1 op:

how use conditional check along in_array($_get['room'], $validrooms)