Samba File permissions for multiple groups in the same general path
 

I'm using my Linux (SLES 10) server as a File Server at this point. I need to set File Permissions to nested folders differently to different groups. For example:
\home\shared\engineering\* should be read only for groupA
\home\shared\engineering\admin should be read & write for groupB Plus read only for groupA
\home\shared\engineering\autocad should be read & write for groupC Plus read only for groupA

I've been using Webmin and Putty to set permissions but Putty only allows me the Default Group, it won't allow me to set several groups on the same directory.

Webmin seems to allow me to add multiple groups (Webmin --> Others --> File Manager --> Info & ACL tab will provide extended abilities) but when I add multiple groups, they don't seem to take effect? I'm wondering if my setup at the 'Share' level or at the hierarchy of my folder structure (unix based) needs to be set specifically?

Am I asking Linux/Samba to do something it's not meant to do?

Your file system has to support ACLs if you want to use them (and you have to enable them).

But it might be simpler to try and live with Linux permissions. You might be forced to introduce additional directory levels, though.

E.g: