User access via NFS is controlled via UNIX-style permissions, read, write and modify. You cannot create an NFS export that controls those permissions - they are only at the filesystem/directory/file level.
You can, however, create multiple NFS exports where one export is read-only and one export is read-write. For example, you can export /ifs/data1 as NFS read-write to a series of clients, then export /ifs/data1 as NFS read-only to a different series of clients. But, again, that does not control user access.
Let me know if that helps!