How to do custom-query based collection mappings in Hibernate?

<set name="ops" inverse="true" cascade="all, delete-orphan">
        <key column="cityblock_id" on-delete="cascade"/>
        <one-to-many class="com.tamedtornado.data.Operation"/>
    </set>

from ops where status="active"

List activeOperations = sess.createCriteria(Operation.class)
    .add( Restrictions.equals("status", "active") )
    .list();