Hello mxc,
i dont know if that instance been shared again.
here is the idea,
any clan leader with x clan level and x players (online)
he go to sing his clan in that npc (more than 2 clans minium, if there is more than 2, example 10 the npc must choose random 2 clans and teleport them to a random place to fight,potions is not allowed, res not allowed, the winners take x reward)
if there is 3 clans registered in that instance the event cancel.or the npc will choose 2/3 random clans and teleport them.
sorry for my bad english i hope you understood it.
thanks for your time.