Add items to router but not links

Question

According to the last paragraph:

https://api.drupal.org/api/drupal/includes%21menu.inc/group/menu/7

Everything described so far is stored in the menu_router table. The menu_links table holds the visible menu links. By default these are derived from the same hook_menu definitions, however you are free to add more with menu_link_save()

I need to do the reverse of that, which API do I use? I need to add a record to the routing table but not couple that to an visible menu link...

The only way I can think (short of manually INSERT'ing) is to initialize a hook_menu call somehow with the various paths I want and call menu_rebuild()??? This appears to be how Panels does it...

Suggestions, opinions, etc???

EDIT | Why isn't this code working...resulting in "The requested page "/test" could not be found."

function test() {
  return 'Do something';
}

function pagegrid_menu_hook() {
  $items = array();

  $items['test'] = array(
    'type' => MENU_CALLBACK,

    'title' => 'TEST',

    'page callback' => 'test',
    'access arguments' => array('access content')
  );

  return $items;
}

Answer 1

Menu links are only created by default because the default type for a router item is MENU_NORMAL_ITEM:

Menu type -- A "normal" menu item that's shown in menu and breadcrumbs.

What you need is a MENU_CALLBACK:

Menu type -- A hidden, internal callback, typically used for API calls.

e.g.

$items['example/feed'] = array(
  'title' => 'Example RSS feed',
  'page callback' => 'example_feed',
  'access arguments' => array('access content'),
  'type' => MENU_CALLBACK,
);

That will create you an accessible path with no menu links, unless of course you add them manually through code or the UI.