Currently the guard command here is fairly iffy, I believe it should always cause the pet to attack whenever what its guarding is hit, regardless of who initiated combat.
This is supposed to be a good way to farm, make b and c guard a and then just use "a kill". a will attack, whenever he is attacked back (instantly), b and c will also attack.
This wouldn't help for pvp at all really, I had quite a few sources on the google group which I seem to have lost, but here's one source to start this off:
http://web.archive.org/web/200008311752 ... amer.shtmlA good trick when you fight monsters or summoned daemons is to make all your pets guard one pet. Then give the 'Kill!' command to that last pet. The monster or summoned daemon will strike back, triggering the guarding pets.
EDIT: Realise thats a UO:R page, but I'm pretty sure there were no changes to guard between T2A and UO:R. What pointed me in the direction of looking at this were era posts on the google groups describing this technique.