Dyna tree selecting multiple nodes programatically not working

Question

In below for loop there are 3 node keys are there but below code is only selecting first key node in dyna-tree other two nodes are not getting selected. please help here i want to select all the 3 nodes i am passing in for loop

function SelectFavouriteValues(result, drpName) {

var responseObject = JSON.parse(result);

//for (itm = 0; itm < responseObject.length; itm++)
//{
    var filterName = responseObject[0].ItemArray[3];
    var filterValue = responseObject[0].ItemArray[4].split(",");

//in below for loop there are 3 node keys are there but below code is only selecting first key in dyna tree other two nodes are not getting selected
    for (i = 0; i < filterValue.length; i++) {

        $(drpName).treeSelect("getDynatreeContainer").dynatree("getTree").getNodeByKey(filterValue).select();
    }
//}   

}