I believe the answer to your question is "Yes". Sitefinity automatically builds an ASP.NET SiteMap from your Sitefinity site structure:http://msdn.microsoft.com/en-us/library/system.web.sitemap.aspx
Most of the main navigation controls Sitefinity comes packaged with appear to utilize this Sitemap. The SiteMap is filtered according to security settings. So, if I have the following Site structure:
...and I turn-off anonymous access for the "Gallery" page; this is how the SiteMap will look to an anonymous user:
Any navigation controls that use the SiteMap will automatically inherit this functionality. Does this help?