I'm sure it's a dumb question but why would you want to have groupwise on OES with NSS? Best practices are to use a native linux file system for GroupWise on linux. We've had that recommendation for a long time and it's very well justified.
Even though I disagree with the choice of ReiserFS as that recommended file system I much more strongly committed to using NSS only in places where I need to have users accessing the file system through a rich set of security assignments like the ones available from Novell NSS trustee assignments. Other than providing NCP access to the Domain for administration from a windows workstation which you can still do using NCP services (shudder to think of using windows) why would any user need direct file access from a windows PC for anything else, never mind requiring trustee assignments?
Would there be perhaps some other function of NSS like salvage that is necessary for GroupWise (again I shudder to think about the mess of leaving salvage enabled on a volume that hosts GroupWise).
I would venture to guess I could accomplish just about everything you'd need to accomplish using native services including copy on write snapshots via LVM.
Not to mention my personal experience with NSS on linux, a great piece of engineering no doubt but not well suited to the kind of transactional load I would expect to experience if I needed to build a 3 node cluster to support the company.
I'm an engineer with over 20 years of experience in the computer field and over 10 years of mechanical engineering before that building theme park attractions and worlds fair pavilions. In all that time one of my most cherished tenets has been to always use the right tool for the job. With that in mind justify to me providing information on using NSS on linux for GroupWise?