Here is an example that will separate family/friends. Unfortunately, it requires your family to use a separate share to see the sensitive files, but they can still get access to the friends area. I know this isn't what you want but it might help.
- Create group "family"
- Create group "friends"
- Create user account "smith" and add to "family" group
- Create user account "share" and add to "friends" group
- Create folder "\\nas\family"
- Grant full access for group "family" to folder \\nas\family
- Grant full access for group "family" to folder \\nas\Qmultimedia
- Grant read access for "friends" to folder \\nas\Qmultimedia
- Put your family sensitive files into \\nas\family
- Put everything else into \\nas\Qmultimedia
- Tell your family to use the "smith" login
- Tell your friends to use the "share" login
Tip: I wouldn't change access rights on sub-folders of Qmultimedia manually unless you are sure that any new files put into those subfolders will inherit the correct access rights. Also rebooting the NAS box may reset some changes (such as umask chown chmod) that aren't done through the web front end, but I haven't tried.
Tip: Create a user account for yourself with the same user/pass you have on windows, then add yourself to administrators. You can map your network drive without being prompted for a password.
Tip: When accessing your files across the internet, only use secure FTP or the SSL login on the QNAP home page. Do not use admin account for standard FTP over the internet.
Tip: You can use the UPnP MediaServer configuration page to add more folders of stuff. So if you have some media you don't want your friends to see, put the media into the \\nas\family share. Use the configuration page to add the \\nas\family share and your UPnP MediaPlayer clients in the house will still see the full listing.
Tip: If you don't trust a friend with full access, don't give it to them. Remember, if you give an account to a friend, chances are 2 buddies of his will get it. Periodically change his password and send an SMS if it is just a casual account.
Tip: Some pasta sauces contain MSG disguised as 'flavour enhancer'.