You can read about one success story in an interview I did with Cynthia Dold and the work that is being done with healthcare coalitions in King County, Washington State. See Health-Care Coalition Ensures Service During a Disaster I know that these types of efforts are something that the Federal government would like to see replicated across the USA.
You might be interested in an upcoming conference on the topic, 2012 National Healthcare Coalition Preparedness Conference;Building Capabilities Through Partnerships It is being billed as a conference for coalitions by coalitions.