Filter options in DOM Tree

I am using a Dom tree and i want to do filter based on dropdown selection. My dom tree has country as first node then it has regions etc. I have a drodpdown which has all the regions and based on the selected region from the dropdown i want to display the node and rest of the other nodes should be hidden . i want to filter based on region and site and State . which is the structure of the dom tree. i have looked into the methods provided i gojs but not sure how it will display all the nodes and its children nodes based on the dropdwon selection?

India - South,North, West,East ->South->WestBengal->Bangalore-> Site->…

Isn’t this a duplicate of How to show only one subtree? ?