[jluerken]

No there is no need to create a template.

Simply use the admincp to create that plugin and enter the forumIDs that should not show up when using the new post search function.

I am excluding the RSS forum for all my users but I never tried to do an exclusion for the admingroup only.
I think it is more or less adding an additional query to check in which usergroup a user is.

Should be easy to find out when you have time to play around with it

I've not tested this but this could work

if ($vbulletin->userinfo['userid'] == YOURUSERID) 
{ 
$vbulletin->GPC['exclude'] .= (($vbulletin->GPC['exclude']) ? ',X' : 'X');  
}

Change YOURUSERID with your userid, for example 1
Change X with the forumID you want to exclude.
Create the plugin like described above

Ok I think I found out how this can work for you

if ($vbulletin->userinfo['usergroupid'] == 6) 
{ 
$vbulletin->GPC['exclude'] .= (($vbulletin->GPC['exclude']) ? ',X' : 'X');  
}

Change X with the forums you want to exclude.
The 6 is the group ID for the Administrator group.

This should work for you