CentOS - Aug 2012 - Samba - Allow writing of files, but not creation of new folders?!?

Greetings- Sorry for the slightly OT post, although this does concern
implementation on a CentOS 5 or 6 server. :)

Long story short, is it possible to configure Samba such that specific users are
able to have 'normal' read/write access on a share, but not the ability
to create new *folders*?

I researched this in the past, and I seem to remember something related to ACLs
or similar, but I'm not finding it now and my attempts at finding info via
the Samba direct resources are coming up dry.

Any thoughts?

--Tim