<?php
$W = new WePay($access_token, $token_secret);

$group_id = apc_fetch('group_id');
$cb = $W->post("/group/callback/$group_id", 
               array('callback_url'=>'http://progphp.com/cb.php'));
print_r($cb);

// Get a list of callbacks for a group
$cbs = $W->get("/group/callback_list/$group_id");
print_r($cbs);