Is it possible to set multiple permission in hook_permission()?
Of course:

function MYMODULE_permission() {
  return array(
    'name of permission' =&gt; array(
      'title' =&gt; t('Access Something'),
      'description' =&gt; t('Access Something to do something'),
    ),
    'name of another permission' =&gt; array(
      'title' =&gt; t('Access Something Else'),
      'description' =&gt; t('Access Something Else to do something'),
    ),
  );
}