multiple logins to directory

[erinatkins]

I am trying to figure out the best way to do this in plesk.

I have 1 site that had been hosted on nt4 that we moved to our plesk machine.

They have a directory called dropbox
In it they have 6 files.
On the first file - they want 1 person to have full control
on 2nd file they just want want another person to have write access & 1 person to have full access
on 3rd file they want someone to have RX & someone to have full control.
etc....

I tried using a secured directory and that does not seem to give me all the permissions I need.

How can I do something like this? Am I missing something?

Thanks
Erin