How to specify a group by field set?

[Joshua Russo]

Is there a way to select a list of group by columns? The aggregation methods seem only apply to a single model but I want to use fields from different models to group by. 

select org.id as organization_id,

       dep.id as department_id,

       cat."catId",

       max(cat.name) as name,

       max(cat."nameDisplay") as nameDisplay,

       count(depItem.id) as itemCount

  from communitynetwork_listcategory as cat 

       inner join communitynetwork_listitem as li on

         li.category_id = cat."catId"

       inner join communitynetwork_organizationdepartmentitem as depItem on

         depItem.item_id = li.id

       inner join communitynetwork_organizationdepartment as dep on

         dep.id = depItem.department_id

       inner join communitynetwork_organization as org on

         org.id = dep.organization_id and

         org.active = True                  

 where cat.name like '%service%' 

    or cat."nameDisplay" like '%service%' 

group by org.id, dep.id, cat."catId"

order by org.name, dep.name, cat.order

This is what I tried to do with a QuerySet that didn't work:

OrganizationDepartmentItem.objects.filter(department__organization__active=True

    ).filter(Q(item__category__name=searchValue) | Q(item__category__nameDisplay=searchValue)

    ).order_by('department__organization', 'department__name', 'item__category__order'

    ).values('department__organization', 'department', 'item__category'

    ).aggregate(Max('item__category__name'), Max('item__category__nameDisplay'), Count('item'))