Group component now supports lists in the config

config/configuration.yaml.example

@@ -56,8 +56,13 @@ device_sun_light_trigger:
 # A comma seperated list of states that have to be tracked as a single group
 # Grouped states should share the same type of states (ON/OFF or HOME/NOT_HOME)
 group: 
-  living_room: light.Bowl,light.Ceiling,light.TV_back_light
-  children: device_tracker.child_1,device_tracker.child_2
+  living_room:
+    - light.Bowl
+    - light.Ceiling
+    - light.TV_back_light
+  children:
+   - device_tracker.child_1
+   - device_tracker.child_2
 
 process:
   # items are which processes to look for: <entity_id>: <search string within ps>

homeassistant/components/group.py

@@ -101,7 +101,11 @@ def get_entity_ids(hass, entity_id, domain_filter=None):
 def setup(hass, config):
     """ Sets up all groups found definded in the configuration. """
     for name, entity_ids in config.get(DOMAIN, {}).items():
-        setup_group(hass, name, entity_ids.split(","))
+        # Support old deprecated method - 2/28/2015
+        if isinstance(entity_ids, str):
+            entity_ids = entity_ids.split(",")
+
+        setup_group(hass, name, entity_ids)
 
     return True