This is gameplay that would be simple in a single-player context; you kill a monster, the monster drops loot, you pick up the loot.
In multiplayer, it's tougher if you want only the highest-damage-dealing player to get the loot. My best guess is that the monster object needs to create an instance variable for every player connected, which increases when that player damages it; when the monster dies, it compares all such variables, selects the player associated with the highest number, and then when that player interacts with the corpse of the monster they get the loot.
...is that possible with the C2 multiplayer object? If so, how?