class BuildingGroup(models.Model):
    description           = models.CharField(max_length=500, null=True, blank=True)
    buildings             = models.ManyToManyField(Building, default=None, blank=True)



class Building(models.Model):
    name  = models.CharField(max_length=120, null=True, blank=True)
    year_of_construction = models.IntegerField(null=True, blank=True)

class DetailBuildingGroupView(StaffRequiredMixin, DetailView):
    model = BuildingGroup
    context_object_name = 'group'
    queryset = BuildingGroup.objects.all()

    def get_object(self):
        id = self.kwargs.get("id")
        return get_object_or_404(BuildingGroup, id=id)

    def get_context_data(self, **kwargs):
        context = super(DetailBuildingGroupView, self).get_context_data(**kwargs)
        bg = BuildingGroup.objects.filter(id=self.kwargs.get('id'))

        arr = []
        for item in bg:
            x = item.buildings.values('name', 'net_leased_area')
            arr.append(x)

        context['buildings'] = bg

        return context

[<QuerySet [{'name': 'TestBuilding', 'net_leased_area': 1234.0}, {'name': 'Another test building', 'net_leased_area': 2242.0}, {'name': 'Crazy new item', 'net_leased_area': 12.0}]>]

data = json.loads(serializers.serialize("json", arr))

result = list(bg.values('name', 'net_leased_area'))
        data = (json.dumps(result))