Guild advancement is crucial in this game. Thus it pays to make one quest count for as much as possible. Have all members sign up for the quest. Upon completion, as soon as the guildmaster starts talking to one player, move on to another. The guildmaster can keep multiple conversations going and can be conned into giving everyone multiple credit for the one event. This also means that it is worthwhile going for multiple roles, so that you can eventually be a level 7 member of every guild.