<?php
class ModulBoxy extends DataObject {
   static $db = array (
'Nazwa' => 'Varchar'
   );
   
   static $has_one = array (
      'Strona' => 'Strona',
      'Page' => 'SiteTree'
   );
   
   public function getCMSFields_forPopup()   {
      return new FieldSet(
new TextField('Nazwa','Nazwa:'),
         new SimpleTreeDropdownField('PageID', 'Select Page:', 'SiteTree')
      );
   }
}
?>

Strona.php

public static $has_many = array(
'ModulBoxy' => 'ModulBoxy'
);

   function getCMSFields() {
      $fields = parent::getCMSFields();

      $manager_boxy = new DataObjectManager(
         $this,
         'ModulBoxy',
         'ModulBoxy',
         array(
            'Nazwa' => 'Nazwa',
'PageID' => 'Page'
         ),
         'getCMSFields_forPopup'
      );

$fields->addFieldToTab("Root.Content.BoczneBoxy",$manager_boxy);

return $fields;
}

<% control ModulBoxy %>
$Page.Title
<% end_control %>

<% if Page.ClassName == Faq %>
do A function
<% end_if %>

<% if Page.ClassName == Faq %>
<% include BoxFaq %>
<% end_if %>

<% if Page.ClassName == Contact %>
<% include BoxContact %>
<% end_if %>

<% control ModulFaq %> // another DataObjectManager with ImageGallery
$Title

<% control Attachment %>
%Title
<% end_control %>

<% end_control %>