If you use View
class like in this example, you can set serialization context with setSerializationContext
method
public function getUsersAction()
{
$data = // get data, in this case list of users.
$view = $this->view($data, 200)
->setSerializationContext(SerializationContext::create()->setGroups(array('list')))
;
return $this->handleView($view);
}