Flex ItemRenderers - global data usages

gistfile1.as

<?xml version="1.0" encoding="utf-8"?>
<mx:DataGrid  width="100%" height="100%"
              xmlns:mx="http://www.adobe.com/2006/mxml" >
				
  <mx:Script>
   <![CDATA[
      /**
       * Array of localized, marker labels 
       */
      public var availableMarkers : Array = [ ];
      
      /**
       * Utility method used by each itemRenderer instance;
       * obviates need to inject markers INTO each instance.
       *
       * @param  j        GroupID used as index into string array
       * @return String   Marker label for the specified groupID
       */
      public function lookupMarker(j:uint):String {
        return (j < availableMarkers.length) ?  String(availableMarkers[j]) : "";
      }
   ]]>
  </mx:Script>
				
  <mx:columns>

    <mx:DataGridColumn  width="55"  headerText="Marker">
      <mx:itemRenderer>

        <mx:Component>
        	<mx:Label text="{ outerDocument.lookupMarker(data.groupId) }" />
        </mx:Component>

      </mx:itemRenderer>
    </mx:DataGridColumn>

  </mx:columns>

</mx:DataGrid>