Sure. You can easily do that with JCR by using relationships. For example, "uses" or "usedby" (depending upon the directions). And its easy to envision lots of other domain-specific and general-purpose relationship types.
One aspect of "understanding" is through reports/analyses. Another is through the UI, providing enough information in a contextual form that the user gets a clear picture of the artifact. In your example of rules, a view/page showing a rule would show all the relationships to other objects, including the "used by" services, and the user should be able to navigate those relationships.
Some relationships are more central to something's description. A service has methods, a table has columns, a class has methods. When getting the information for any object, DNA should bring in those highly-related objects to construct as complete of a view as possible. This functionality is part of the DNA View system, which allows users to define their own views specific to their domain of use.