How can a group id, be droped?

[KONSTANTAS Dimitri]

Its been sometime ago that I am puzling myself with the question,
"how to drop a group id".
As known 4.[123] systems assign to each user process a list of
group ids.
Can a simple user "drop" one or more of the group memberships in one process?
For example, if a user belongs to groups
	local
	news
	research
is it possible to create a process that will belong to only, say,
	local
	news ?

I wonder if any of the Wizards or gurus out there in the
net-land knows how and if that can be done!

All sugestions are wellcome!

Dimitri Konstantas
University of Geneva

uucp: mcvax!cernvax!cui!dimitri
BITNET: dimitri at cgeuge51.bitnet