Retriving users from group ?...

Hello all!!!

I need to retrieve all the users from a group, for my Delphi
Interface for PostgreSQL.
The problem is, I can't accomplish a query that does it, since the
users belonging from a group are all stored in an array field
(pg_group.groulist).
Does anyone have a solution for this ? Using contrib array functions
is certainly not a good idea, because it would require ALL users of the
interface to compile and install it.
I still don't understand anyway why there is not a regular catalog
relating users and groups, like:

CREATE TABLE pg_groupusers(grosysid integer, usesysid integer);

That makes much more sense for me, unless at least the contrib array
functions get implemented as builtins, so that we can test user groupship.
Can that be added to the TODO least ?...

Best Regards,
Steve Howe