Since 6 players can play at once with their own list of items. If the same item is on more than 1 player's list, do they see the same item and it can be picked up by each player, or they see their own instance of the item and they pick up their own copy? Are the items in different locations per player?
Considering the dynamics here, I would say spawning the items for each player and only allowing that player to see their own items might be the way to go here. Alternatively you could just pool all the items from everyone's list and only spawn 1 copy of each item into the world and set who can see the items to only those who have it on their list, and remove them from being able to see it after they've already grabbed it.