On the following Dojo example
you will find a basic Kendo UI TreeView implementation in AngularJS, where a similar scenario to the one described is demonstrated.
You will notice that in order to determine the drop target, I have used the TreeView's drop event
dropTarget = e.dropTarget,
dropTargetText = $(dropTarget).text();
"Drop target text: "
You can use this event to verify if the drop target is equal to some expected value and then apply your custom logic depending on your application requirements.
I hope this helps. In case you have any other questions related to the TreeView widget, please do not hesitate to contact us.