elasticsearch combining AND and OR - possible?

gistfile1.txt

// (name.second == ba || name.second == po) && postdate ...

filter': {
        'and': [
                {
                    'or':[
                          {
                             "prefix" : { "name.second" : "ba" }
                          },
                          {
                             "prefix" : { "name.second" : "po" }
                          }
                      ]
               },
              {
                    "range" : { 
                        "postDate" : { 
                            "from" : "2010-03-01",
                            "to" : "2010-04-01"
                        }
                    }
              }
            ]
}