This custom agreggator for Scatter-Gather was the only solution I've found to aggregating multiple collections with the same root tag

CustomAggregator

package org.hoeggsoftware;

import org.mule.api.MuleEvent;
import org.mule.api.MuleException;
import org.mule.api.context.MuleContextAware;
import org.mule.api.routing.AggregationContext;
import org.mule.routing.AggregationStrategy;
import org.mule.api.MuleContext;
import org.mule.api.routing.RouterResultsHandler;
import org.mule.routing.DefaultRouterResultsHandler;

/**
 * @author <a href="mailto:[email protected]">David L. Whitehurst</a>
 *
 */
public class CustomAggregator implements AggregationStrategy, MuleContextAware  {
	
	private RouterResultsHandler resultsHandler = new DefaultRouterResultsHandler();
	private MuleContext muleContext;	

	@Override
	    public MuleEvent aggregate(AggregationContext context) throws MuleException {
	        MuleEvent result = null;
//	        for (MuleEvent event : context.collectEventsWithoutExceptions()) {
//	                result = DefaultMuleEvent.copy(event);
//	                result = resultsHandler.aggregateResults(eventsWithoutExceptions,	context.getOriginalEvent(), muleContext);
//	        }
            
	        result = resultsHandler.aggregateResults(context.collectEventsWithoutExceptions(),	context.getOriginalEvent(), muleContext);
	        
	        for (MuleEvent event : context.collectEventsWithExceptions()) {
                System.out.println(event.getMessageAsString());
	        }
	        
	        if (result != null)  {
	            return result;
	        }
	         
	        throw new  RuntimeException("Scatter-Gather data could not be collected!");
	    }
	
	@Override
	public void setMuleContext(MuleContext context) {
		this.muleContext = context;
	}	
	
}