final List<String> groupNames = ObjectSpecifications.orderByMemberGroups(objectSpec, associationsByGroup.keySet(), hint);
columnRepr.memberGroups = Maps.newLinkedHashMap();
for (String groupName : groupNames) {
final MemberGroupRepr memberGroupRepr = new MemberGroupRepr();
columnRepr.memberGroups.put(groupName, memberGroupRepr);
final List<ObjectAssociation> associationsInGroup = associationsByGroup.get(groupName);
memberGroupRepr.members = Maps.newLinkedHashMap();
if(associationsInGroup == null) {
continue;