3 Level Approval Hierarchy required for Project Invoices

We have following business requirement for InterProject Contract Invoices -

1) If Invoice amount is less than 5 million then the approval notification should go to 'Project Accountant N3' role.

2) If Invoice amount is between 5 million to 10 million, then the approval notification should first go to 'Project Accountant N3', once the approval is done by N3, the notification should be sent to 'Project Accountant N4' role

3) If Invoice amount is above 10 million then first notification should be sent to 'Project Accountant N3', post approval from N3, the next notification should go to 'Project Accountant N4', once approval is done by N4, then it should go to 'VP Finance' for approval.