How to route expense report approvals to the manager of default cost center of the employee?

Summary:

How can we route the expense report approval to the manager of the default cost center of the employee, even if the items in the expense reports are charged to different cost centers (Other than default cost center).

Content (please ensure you mask any confidential information):

How can we route the expense report approval to the manager of default cost center of the employee/owner of the expense report. This should be irrespective of which cost center is selected on the expense items while submitting the expense report. The requirement is to route approvals to the employee's default cost center manager only even if the report has been split to 2 or more cost centers.