Create two collections of Type : Bill and enable the attribute Cleared in one collection and disable the attribute Cleared in another collection. Subsequently, create a Union of both these Collections.
Example
[Collection: List of Cleared Bills]
Type : Bill
Cleared: Yes
[Collection: List of UnCleared Bills]
Type : Bill
Cleared: No
[Collection: List of Bills]
Collection: List of Cleared Bills, List of UnCleared Bills