Your memory sucks, Metallikus/Xanthias... sorry, bros. Definitely classic.
http://mmoplayer.wikidot.com/everquest
"Another unique aspect of playing Everquest was trains. Not mechanical locomotives but long parades of monsters chasing a player or group of players. Trains arise from a combination of factors. The first thing required for a train is for a player or group to aggro more monsters than they can handle. Once the monsters start attacking a player they will not stop until either the player is dead or leaves the region by zoning out (crossing a line where the server removes them from the current area and loads them into the next).
A monster will aggro on every player that it comes near making the train dangerous not only to the person being chased but to everyone it runs past as well. If a skeleton is chasing Brutus to the zone line and they pass nearby, as soon as Brutus zones out or dies that skeleton, and every other monster they pass on the way, is going to come after you."
He stopped playing before Kunark:
"
At some point when my character was in the mid 40's (and the level cap was still 50) I suddenly suffered a disconnect between the game world and the game mechanics. No longer was I an adventurer killing monsters. Instead I was a person sitting at a keyboard watching a progress bar advance pixel by agonizing pixel."
So unless there's proof the aggro system changed in Kunark (which it could have, since Kunark also introduced mobs stopping pursuit after you got a certain distance away, but resuming pursuit once you enter back in range, and that's not implemented here either...), the mobs SHOULD add KOS players in aggro range to their aggro list even if there is someone else already on the aggro list.