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Yes it is. You can create custom html pages using (say) the TinyD module. Then create a new custom group (system -> groups) and set your permissions to only allow that group to access/view it.
You can build custom menus with Multimenu, but you might not need to - if you just want the link to appear in the main menu, groups that can't access module won't be able to see it anyway.
Some modules also have category-level permission systems built in (eg. WF-downloads) so you can create private sections of some modules as well.
[Please don't double (or triple!) post your questions in the forums - once is enough].