How can I connect two parent node into one child node and how to make a tooltip for each node in the tree pragmatically? in D3 js (SVG)

[Shankhadeep Bhadra]

I have made a tree graph structure and it's working absolutely fine. But now I want to make a small change but unable to make that change. I want to connect the two-parent node into one child node...also I am trying to add a tooltip into each node pragmatically.

example - if you run the code, you will see it more clearly. I wanna make a child node od Hanna and mark which will be connected to a child node named "Eric".

any idea how to achieve this? - giving the stackoverflow link - https://stackoverflow.com/questions/64587495/how-can-i-connect-two-parent-node-into-one-child-node-and-how-to-make-a-tooltip