Block holiday request/booking for staff where dates clash with team members

We have holiday requests set up via email so the line manager can approve/decline accordingly. However, we've recently had some situations where critical teams have had members on holiday at the same time, because the line manager has authorised without checking who else is on holiday. I've been asked to find out the possibility of having something in the People system which stops holiday being requested on the same dates by team members (provided they are set up in the same department). For example Employee A books/requests 5 days in December, which is authorised. Some time after, Employee B also tries to book/request same 5 days as Employee A - can this be set so that Employee B cannot book/request those dates? Or an alert comes up to warn Employee B that holiday dates are blocked due to team member has existing booking so contact line manager?