Intercepting the hire process to see if Employee already exists in the Student Database

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During the employee hire process in Oracle HCM, we would like to check against our student system to see if the employee is already part of the institution (i.e: Student). If the Employee happens to be a student, we would like to bring in some of the information from Student system into HCM (ie: API checks to see if user exists in the Student system using whatever information we provide and return a value).   In looking at the delivered hire process, I did not see a way to interrupt the process to do this.   If you have any thoughts on how