Permissions for FTP access

[Razorblade]

Following problem:

I am running an FTP server. Every user's initial directory is /FTP
There are several directories within /FTP: A, B and C.

How is it possible that user Joe has read only access to directory A, while he's not able to see directories B and C.
User John can read/write to A and has read only access to B and C.
User Greg has read/write access to C and read only access to B and can not see A.

How can this be done?

What I thought was to define several groups:
Read_A
Write_A
Read_B
Write_B
[...]

And then assign those users to the corresponding groups. But what next? How can I assign more than one group to one directory?
Also I need a group e.g. ftp-admin that has r/w access to all those mentioned directories and can create/delete directories within /FTP.

No other user or anonymous is allowed to log in or see anything.

Using Fedora 8 i386 with proftp

[nix4me]

The easiest way to do this, in my opinion, would be to use proftpd. Proftpd allows for setting very specific dir permissions in the config file. Take a look at the 'limit' parameter. It will allow you to set a stanza for each dir and then allow you to define which users have which access to each dir.

Look at the limit directive in the proftpd documentation and I think you will see the endless capability.

[Razorblade]

Thank you very much.
That did the trick.

RTFM