cldArticle.setProxyClassName(null);
broker.getDescriptorRepository().setClassDescriptor(cldProductGroup);
broker.getDescriptorRepository().setClassDescriptor(cldArticle);
Criteria crit = new Criteria();
crit.addLessOrEqualThan("groupId", new Integer(5));
QueryByCriteria q = QueryFactory.newQuery(ProductGroup.class, crit);
q.addOrderByDescending("groupId");
q.addPrefetchedRelationship("allArticlesInGroup");
Collection results = broker.getCollectionByQuery(q);