Your problem can easily be solved using sections. More info here http://ez.no/doc/ez_publish/technical_manual/3_8/concepts_and_basics/content_management/sections
Create a section and add content to it. Then add permissions to groups and/or users that you want to give access to that section.
It might be easier just to hide the content in the admin - either in the "locations" box or using the contextual popup menu in the Content Structure menu (look under Advanced - Hide/Unhide).
This will prevent the pages from being seen on the user siteaccess as long as that setting is not overridden (show hidden nodes in site.ini.append.php).
