How to upload files onto two different folders depending the category type? (and one of them be private)

Can this be done?
I have two different kind of files: The public and the private ones.
I´ve posted several issues and forum requests, but still didn´t get an answer: I need to create nodes with several attachments each, that are not available for anonymous users. But I need to create nodes with attachments available for all too!

So I´ve thought that maybe I could create one folder inside the "files" one, wich could be password protected, and add all the "private" attachments there... But I still want to be able to add normal free-access attachments also.

This seems to be complicated... there must be an easier way... I hope so.

Is there a way to do this??

Thanks for all the help!!!!!!!!!!!!

Rosamunda