`competencyRequired` in the KH: as string and `LearningResource`

In the current KH schema, the field competencyRequired requires a string; but on the N4E eduTrain platform, the competencyRequired for some courses is another course (LearningResource) (example1, example2). Would it be feasible to make the field competencyRequired accept both string and LearningResource, or what if creating a new field in the schema to handle the case where a LearningResource is the prerequisite of another LearningResource?