whmcsTools/get_groupid.php

<?php

/**
*/

use Illuminate\Database\Capsule\Manager as Capsule;

function current_groupid_hook($vars)
{
   $serviceId = $vars['serviceid'];
   $productId = Capsule::table('tblhosting')
       ->where('id',$serviceId)
       ->value('packageid');
   $groupId = Capsule::table('tblproducts_slugs')
       ->where('product_id',$productId)
       ->value('group_id');
   return array("gid" => $groupId);
}
add_hook("ClientAreaProductDetailsPreModuleTemplate", 1, "current_groupid_hook");