Well for my sub-job quest we had to be competitive, the Selbina one had Ghouls and they are rare, so we have to compete with everyone else. Its a simple we find and claim it first thing. Because i am pretty sure prolly that the other party needs the items too, and well thats the only real competition there is. I usually let them have it if its close or something, but if its rare then most wont let the other get it since it can be an hour at least before they see another of the same monster.

O and if ur lvl 18 dont do that Mhuara quest...its for lvl 28 and up because Bogys are real hard, you need an alliance of well-trained people in order to win and the chances are that the lot wont be yours. Or you can ask a friend that is of higher lvl to party and get it for you. Once you accept the quest tho, theres no changing it from Selbina and Mhuara.