diff --git a/backend/Property.py b/backend/Property.py
index c54405b2..72d1d169 100644
--- a/backend/Property.py
+++ b/backend/Property.py
@@ -60,6 +60,7 @@ class Property:
     # Surplus information, that can be provided as optional inputs, by a customer
     n_bathrooms = None
     n_bedrooms = None
+    building_id = None  # Used to group properties together into a single building
 
     def __init__(
         self,
@@ -193,12 +194,14 @@ class Property:
         return {
             "n_bathrooms": n_bathrooms,
             "n_bedrooms": n_bedrooms,
+            "building_id": kwargs.get("building_id", None),
         }
 
     def parse_kwargs(self, kwargs):
         # We extract the elements from kwargs that we recognise. Anything additional is ignored
         self.n_bathrooms = kwargs.get("n_bathrooms", None)
         self.n_bedrooms = kwargs.get("n_bedrooms", None)
+        self.building_id = kwargs.get("building_id", None)
 
     def create_base_difference_epc_record(self, cleaned_lookup: dict):
         """
diff --git a/backend/app/plan/router.py b/backend/app/plan/router.py
index 0cf670c2..2832989e 100644
--- a/backend/app/plan/router.py
+++ b/backend/app/plan/router.py
@@ -263,7 +263,6 @@ async def trigger_plan(body: PlanTriggerRequest):
             bucket_name=get_settings().DATA_BUCKET, file_key="sap_change_model/cleaning_dataset.parquet",
         )
 
-        # TODO: insert building id
         input_properties = []
         for config in tqdm(plan_input):
             # We validate each record in the file. If the record is NOT valid, we need to handle this accordingly
@@ -366,9 +365,22 @@ async def trigger_plan(body: PlanTriggerRequest):
         for p in input_properties:
             p.get_components(cleaned, photo_supply_lookup, floor_area_decile_thresholds, energy_consumption_client)
             p.get_spatial_data(uprn_filenames)
-            # Call Google Solar API
-            # TODO: Complete me
-            solar_performance = solar_api_client.get(longitude=p.spatial["longitude"], latitude=p.spatial["latitude"])
+
+        building_ids = [
+            {
+                "building_id": p.building_id, "longitude": p.spatial["longitude"], "latitude": p.spatial["latitude"]
+            } for p in input_properties if p.building_id is not None
+        ]
+        if building_ids:
+            # Model the solar potential at the building level
+            print("complete me")
+        else:
+            # Model the solar potential at the property level
+            for p in input_properties:
+                # TODO: Complete me!
+                solar_performance = solar_api_client.get(
+                    longitude=p.spatial["longitude"], latitude=p.spatial["latitude"]
+                )
 
         logger.info("Getting components and epc recommendations")
         recommendations = {}