More detailed information can be found on my blog about the ESB.Extensions:
http://geekswithblogs.net/BVeldhoen/archive/2009/09/11/debatching-aggregation-and-resequencing-using-the-esb.extensions.aspx
http://geekswithblogs.net/BVeldhoen/archive/2009/08/28/my-beef-with-the-esb-toolkit-2.0-resolution-framework.aspx