[Samba] NTFS-type directory permissions

[Michael Flatley]

I apologize if this is an easy question.  I am a samba newbie and the
answer was not really clear to me from reading chpt 12 of the
documentation.

We recently moved from a Windows 2000 file server to a Samba(3.0.4)
file server running on Solaris.  We have about 20 top-level
directories with lots of subdirectories.  Right now, we have the
security setup so that people can only get to the top-level
directories that they should have access to.  This is ok for now, but
at some point we would like to get back to the way it was under NT. 
We have not figured out a way to control the permissions underneath
these top-level directories.

For example:
The user is mapped to a single share that contains all of the folders
(can't be more than one share since users need to access the folders
from windows using the same drive letter).
That share contains:
Admin
Helpdesk
Finance
HR
etc.

The particular user only has access to the HR directory which contains:
Paychecks
Personnel
List
etc.

Now, this user should only have read access to List, no access to
Personnel, and write access to Paychecks.  In our current setup, he
has write access to all these folders because they are only controlled
by the top-level, HR, which has the Unix permissions:

rwxrwx---   root  hr
(the user is a member of hr)

Is there a way that we can have more control over the directories and
files?  Can someone give me some example configurations or point me to
a past post or something?

Thanks