User-specified file sharing

[Gary Mills]

Does anyone know of a way that groups of users can share files among
themselves without requiring action by the administrator?  Just making
the file world-readable is not a solution, so it would have to involve
group permissions.  Some users allow sharing via .rhosts files, but
this can become a security nightmare because the whole account is shared.
We run SunOS 4.1.1, NFS, and NIS, if it matters.
-- 
-Gary Mills-         -Networking Group-          -U of M Computer Services-