kendo treeview multiple node drag and drop

Question

I have One Kendo Tree-view with check-box. I am able to drag and drop single item(node).Now I want to drag and drop multiple Item(node). only those nodes will be drag and drop which check-box are checked. Please help me out how can be i implement this functionality.........

for single drag and drop i am following this example----

http://demos.telerik.com/kendo-ui/web/treeview/dragdrop.html

USER CAN ABLE TO DRAG AND DROP AS MANY NODES HE SELECTED IN CHECKBOX.

According to MY RND

Below code section from kendo.web.js

     dragstart: function (e) {
        /*  Here Kendo UI StartDRAGGING*/

        console.log(e);
        var that = this,
            treeview = that.treeview,
            sourceNode = that.sourceNode = e.currentTarget.closest(NODE);

         // here how can i find how many node are selected 

        if (treeview.trigger(DRAGSTART, { sourceNode: sourceNode[0] })) {
            e.preventDefault();
        }

        that.dropHint = $("<div class='k-drop-hint' />")
            .css(VISIBILITY, "hidden")
            .appendTo(treeview.element);
    }