|------------------|
           | filter           |
        |--|  - input bound   |--|
        |  |  - predicate     |  |  |------------------|  |------------------|
        |  |------------------|  |  | filter group     |  | filtered list    |
input --|                        |--|  - combined      |--|  - uses combined |
        |  |------------------|  |  |    predicate     |  |    predicate     |
        |  | filter           |  |  |------------------|  |------------------|
        |--|  - input bound   |--|
           |  - predicate     |
           |------------------|