The Artifact should store a list of all nodes created by its processing.
Keep in mind that during graph opening the ArtifactId (or its sha1) can be used as a parameter.

It can be implemented using the Graph itself. Creating a Node representing the Artifact in a special context.

Other nice use of this special context is to trace the history of an artifact like:
This artifact is on these paths.. and later this artifact on a specific path has been changed and so on...