Not sure that I understand the question - you can select any Node in a Utility Network from the project Explorer Tree or by Clicking on them graphically - when they are selected they are selected - not sure what you are asking here.
A Utility Node can be used in 1, 2 or more Runs - in the case of a Fitting that could be a T or an X fitting for example.
Can you give me a little more detail Layne?
Alan