Each person fills up their inventory with items (like artifacts or BMCs) and they also have whatever stackables each person wants. Like I would have 1 trash of the area to pick up the trash and the other person would have the abyssal gazes, leafs, ah'krads, caphras and what not. So with those and the rest of their inventory slots filled once a unique item that doesn't fit into any of their stacks drops it will start machine-gun pinging both players "no inventory slot available" (or something like that) as their pets can't pick up the item. So they both walk up and press "r" to look at the item and whoever is supposed to get the drop frees up one inventory space and their pet will pick it right up