I think you can! Someone on msdn posted the following:
Audience Targetting
I'd recommend at dividing your users into SharePoint groups. You can
then use Audience Targeting to set who can or can not see specific
links (Site settings > Navigation). For audience targetting, you
target SharePoint groups, AD groups or specific users. Please
remember that Audience Targetting is not a security trimming.
Security Trimming
If you'd like to limit who can see items in the navigation, then
SharePoint will manage the navigation that based
on the permissions. You just have to make sure that security is
defined properly for each site, list library, document library or any
specific item you have in your navigation menu.
so if you put the users into groups and then you can set permissions to that group if they are allowed to certin parts and let sharepoint handle the hiding and showing :)
http://social.msdn.microsoft.com/Forums/en-US/sharepoint2010general/thread/1aabad61-d039-4b05-a86c-8fb854031a67/