How do I create system dependency mapping?

Hi there,
I am looking to map dependencies of different IT systems.
My data (a .csv file) is in he following structure (obviously different system names and additional fields):


What I want to be able to do is:

  1. Import the csv into Neo4j, and create an object for each system. Ideally, I can create the relationship (DEPENDS_ON) through the import process.
  2. Analyze which are the most critical systems. In the case above, system D will be considered critical since many other system rely on it. At the same time, system E will be critical since everything else
    depends on it (directly and indirectly) - it is at the "root" of this dependency tree.

*Note: In my case, there are hundreds of systems and potentially several roots to be discovered.

How can I do this?

Thank you!!