Validation on Enroll button in Learning Catalog

Summary:

Content (please ensure you mask any confidential information):

We have a requirement to apply a validation when the employee is trying to request/enroll him self in a course for the below cases:
  1. The Course Offering Activity Start Date and End Date overlap with an absence/leave record
  2. Employee is a blacklisted employee (Black listed employees are identified via a DFF in the Assignment screen)

The Catalog Details Page is a read only form when extended onto VB Studio with no configurable section. 

Please let us know if there is a workaround that can be adopted to add a validation to the Enroll button.