diff --git a/SAS/TMSS/src/tmss/tmssapp/schemas/UC1-scheduling-unit-observation-strategy.json b/SAS/TMSS/src/tmss/tmssapp/schemas/UC1-scheduling-unit-observation-strategy.json
index 183f8933332dd016194b939315b4bc25a9c3d183..9e917e322eea7f4f7495828ef9a4d5581dffc2ef 100644
--- a/SAS/TMSS/src/tmss/tmssapp/schemas/UC1-scheduling-unit-observation-strategy.json
+++ b/SAS/TMSS/src/tmss/tmssapp/schemas/UC1-scheduling-unit-observation-strategy.json
@@ -62,7 +62,20 @@
         },
         "antenna_set": "HBA_DUAL_INNER",
         "filter": "HBA_110_190",
-        "stations":["CS001"],
+        "stations": [
+          {
+            "group": "DUTCH",
+            "max_missing": 4
+          },
+          {
+            "group": "INTERNATIONAL",
+            "max_missing": 2
+          },
+          {
+            "group": "INTERNATIONAL_REQUIRED",
+            "max_missing": 1
+          }
+        ],
         "tile_beam": {
           "direction_type": "J2000",
           "angle1": 0.42,
diff --git a/SAS/TMSS/src/tmss/tmssapp/schemas/common_schema_template-stations-1.json b/SAS/TMSS/src/tmss/tmssapp/schemas/common_schema_template-stations-1.json
index b2da0323b13d085e1932349a6fadd2a9b82f768d..9d9fc6adf1920e58b46682f7bc32624bdd4a9fa9 100644
--- a/SAS/TMSS/src/tmss/tmssapp/schemas/common_schema_template-stations-1.json
+++ b/SAS/TMSS/src/tmss/tmssapp/schemas/common_schema_template-stations-1.json
@@ -89,12 +89,11 @@
     "station_constraint":{
       "type":"object",
       "default":{},
-      "additionalProperties":false,
       "oneOf": [
         {
           "title":"Custom list",
           "properties":{
-            "stations":{
+            "list":{
               "title":"Stations",
               "description": "Custom station selection",
               "$ref": "http://tmss.lofar.org/api/schemas/commonschematemplate/stations/1#/definitions/station_list",
@@ -105,7 +104,7 @@
               "default":0
             }
           },
-          "required":[ "stations", "max_missing" ]
+          "required":[ "list", "max_missing" ]
         }, {
           "title": "All",
           "properties":{
@@ -205,7 +204,7 @@
       "minItems":1,
       "default": [ {
         "group": "ALL",
-	"stations": [],
+	    "list": [],
         "max_missing": 0
       } ]
     },
diff --git a/SAS/TMSS/src/tmss/tmssapp/schemas/task_template-target_observation-1.json b/SAS/TMSS/src/tmss/tmssapp/schemas/task_template-target_observation-1.json
index f6e92bc010d32d7e20cc879dfe7576fd18dfdb71..27ffc2d55403fa70f926ff1a6613139ec61be5af 100644
--- a/SAS/TMSS/src/tmss/tmssapp/schemas/task_template-target_observation-1.json
+++ b/SAS/TMSS/src/tmss/tmssapp/schemas/task_template-target_observation-1.json
@@ -8,7 +8,7 @@
   "properties": {
     "stations": {
       "$ref": "http://tmss.lofar.org/api/schemas/commonschematemplate/stations/1#/definitions/stations",
-      "default": ["CS001"]
+      "default": [ {} ]
     },
     "antenna_set": {
       "$ref": "http://tmss.lofar.org/api/schemas/commonschematemplate/stations/1/#/definitions/antenna_set",
diff --git a/SAS/TMSS/src/tmss/tmssapp/subtasks.py b/SAS/TMSS/src/tmss/tmssapp/subtasks.py
index 87189cc5cb1307e30073ba8d47309b583719d6f0..1a7c995a452e6d40e0f6f8aa4bd62cb1fc28cd44 100644
--- a/SAS/TMSS/src/tmss/tmssapp/subtasks.py
+++ b/SAS/TMSS/src/tmss/tmssapp/subtasks.py
@@ -129,16 +129,25 @@ def create_observation_subtask_specifications_from_observation_task_blueprint(ta
     subtask_spec['stations']["filter"] = task_spec["filter"]
 
     if "stations" in task_spec:
-        if "group" in task_spec["stations"]:
-            try:
-                # retrieve stations in group from RADB virtual instrument
-                station_group_name = task_spec["stations"]["group"]
-                subtask_spec['stations']['station_list'] = get_stations_in_group(station_group_name)
-            except Exception as e:
-                raise SubtaskCreationException("Could not determine stations in group '%s' for task_blueprint id=%s. Error: %s" % (
-                    station_group_name, task_blueprint.id, e))
-        else:
-            subtask_spec['stations']['station_list'] = task_spec["stations"]
+        subtask_station_list = []
+        #  task_spec["stations"] is a list
+        for station_item in task_spec["stations"]:
+            if "group" in station_item:
+                station_group_name = station_item["group"]
+                try:
+                    # retrieve stations in group from RADB virtual instrument
+                    subtask_station_list.extend(get_stations_in_group(station_group_name))
+                except Exception as e:
+                    raise SubtaskCreationException("Could not determine stations in group '%s' for task_blueprint id=%s. Error: %s" % (
+                        station_group_name, task_blueprint.id, e))
+            elif "list" in station_item:
+                subtask_station_list.extend(station_item["list"])
+            else:
+                logger.info("NO 'group' or 'list' in task spec, so nothing to be added to station list")
+        subtask_spec['stations']['station_list'] = sorted(list(set(subtask_station_list)))
+    else:
+        logger.info("NO stations defined at all")
+    # TODO: Do something with max_missing
 
     if 'calibrator' not in task_blueprint.specifications_template.name.lower():
         # copy/convert the analoge/digital_pointings only for non-calibrator observations (the calibrator has its own pointing)
@@ -173,6 +182,16 @@ def create_observation_subtask_specifications_from_observation_task_blueprint(ta
 def get_stations_in_group(station_group_name: str) -> []:
     '''Get a list of station names in the given station_group.
     A lookup is performed in the RADB, in the virtual instrument table'''
+
+    # TODO Make names RA and TMSS spec equal: 'NL' or 'DUTCH'?
+    if station_group_name == "DUTCH":
+        station_group_name = "NL"
+
+    #International required is by defintion DE601 or DE605, take 601 for now
+    # TODO check with RA the availability of both stations
+    if station_group_name == "INTERNATIONAL_REQUIRED":
+        return ["DE601"]
+
     with RADBRPC.create() as radbrpc:
         resource_group_memberships = radbrpc.getResourceGroupMemberships()['groups']
         station_resource_group = next(rg for rg in resource_group_memberships.values()
@@ -184,6 +203,10 @@ def get_stations_in_group(station_group_name: str) -> []:
         if 'RS408' in station_names:
             station_names.remove('RS408')
 
+        # HACK remove TEST1 from station list otherwise validate will fail
+        if 'TEST1' in station_names:
+            station_names.remove('TEST1')
+
         return sorted(list(station_names))