newgrp in shell programs

[Bruce W. Mohler]

Is it possible to do a newgrp near the beginning of
a shell program (especially one that has been started
by cron)?  Everything that I've tried has failed (ie.,
the shell program stops right at the point that it does
the newgrp).

I understand that newgrp creates a new shell process,
but knowing this has not helped me to figure out whether
what I want to do is possible...

I've tried to RTM before asking this (going thru all of
Sys Admin UNIX manuals we have as well as all of the 
"after-markey" Sys Admin books that we have on site).

Local security measures prevent me from using a "generic"
or impersonal userid (like lpadm) which has the group to
begin with, then letting that userid "own" the cron entries.
My only alternative (as far as I know) is to find some way 
to newgrp in these shell programs.

Environment: CCI Tahoe boxes (UNiSYS lables)
	     UN|X OS level 2.21 (which is a mutation of mostly
		BSD 4.2 with some SYSV.2 thrown in to make 
		things fun)
	     Shell: plain (good ole) Bourne

All suggestions and directions are appreciated, in advance!!!!
-- 
Bruce W. Mohler
Systems Programmer (aka Staff Analyst)
bruno at sdcc10.ucsd.edu
voice: 619/586-2218