I believe I've read that exp parties do work, and are actually faster than fates. Get a group of 8 people together and go find a decent set of mobs that spawn fast and are around 5 levels above the players. I've heard that chaining in this fashion gets tons and tons of exp. The main hindrance to this is that you can't arbitrarily level sync down to another players level. So variation in group levels can make this rather difficult to create a party for.