There is no game sided enforced looting system that determines who will gain the item. Instead it is solved trough human interaction.
The classical way to determine who will gain a item is to dice for it. Leader of the party call's for party dice and whoever rolls the highest, gets to pick first while others follow in order. If number of items exceed the number of pickers involved, the first one picks a second item.
Variation from regular dice that has more items than pickers. After reaching the smallest roller, instead of hopping back to the highest roller, the picking starts in reverse order. Benefit from this is that the lowest rollers will most likely get two mediocre or minor items while the high rollers get only one superior item and possibly minor ones.
aka Lucky dice. Calling for a dice for each item separately.
In God we trust, all others pay cash. Using the in-game currency to determine who will get the item.
Each item is sold for the highest bidder and the income is divided among the group. To gain best possible price for the item, offers from outside of the group may also be taken.
The player gets paid for his troubles, but in turn forfeits his share for the loot.
Most SS+es determine who will get the item by keeping track how much the person has made items in that particular SS+. From each item made he gains portion of its price to himself. When person has gained more points that the items price or he is in positive points, the item is delivered to him. Note that most guilds don't use true DKPs system as trading SS+ points are allowed and quite common.
Items price starts from minimal and the one having the highest bid when the biding time closes, wins the item.
Each item has predetermined price that is usually determined by the leaders of the SS+ or mimicked from some other SS+. When person pays the amount, he is entitled for it.
The leaders of the SS+ might have restricted who are allowed to bid for items and/or how much of points are allowed to use in bidding.
Leader of the party might demand for special benefits for leading the group.
Number added to leaders dice roll(s) or increased percentage of point gain.
The leader collects all high coins made by the party.