W2K security for Oracle directories?

We have 19 local development oracle instances in my shop.

    Oracle 9.2.0.1.0
    Windows 2000 Server

I'm trying to set it up so all developers have shared their
"c:/oracle" with an NTSecurity group called ourdbas (which
contains me and the rest of the database team). I can then do behind the scenes maintenance of their local development instances without their having work stoppages.

I first tried having them share the "c:/oracle" directory with that NTSecurity group, but that still didn't allow us to create or delete any files on their drives. I then had one of them modify the security settings of that drive. Even, here, I couldn't quite make sense of the security mechanisms of NT and Oracle together. If I try to revoke access to everyone and grant access to that group, I get "Deny entries take priority over Allow entries, which can cause unintended effects due to group memberships". Even though there won't be any harm done to some development box, I would rather that they don't share the
"c:/oracle" with everybody. Instead, I would like to understand
how to implement this as though the instances actually had importance and needed to be locked down appropriately.

So, what do I need to have a developer do so that he shares his Oracle drive with that dba group but not with the whole world?

Thanks.

-- 
Galen Boyer