1. A method of tracking items in a cluster of items having a first subset of items and a second subset of items mutually exclusive from the first subset of items, the method comprising: receiving a signal associated with an item in the first subset of items, the signal being indicative of an identifier associated with the item in the first subset of items; obtaining an item record associated with the item in the first subset of items based on the identifier associated with the item in the first subset of items; and obtaining an item record associated with an item in the second subset of items based on a linking between the item record associated with the item in the first subset of items and the item record associated with the item in the second subset of items.