Feasibility to create custom validation msg for internal candidate job application screen/page

Hi,

We received requirement as below:

1. Any employee belonging to Grade 1 or 2 should not be allowed to apply for any job on the internal career site page —> therefore, IFF any employee tries to apply to a job the customer wants the system to throw a Validation message in form of an ERROR msg on the internal candidate job application screen.
2. Any employee having less than 1 year in the company should not be allowed to apply for any job on the internal career site page —> therefore, IFF any employee tries to apply to a job the customer wants the system to again throw a Validation message in form of another ERROR msg on the internal candidate job application screen.