Question about VirtualNode

[Yedaxia1]

I want to add a virtual node to the graph, but I don't want to connect the whole graph, just some nodes in it. How should I do this?
For example: there is a node V={0,1,2,3,4} in the graph, I want to add a node s, connect {s,0},{s,2}, how to realise this is relatively simple.