"Multi-Subsidiary" Employee

Hello.

Does anyone have a work around for this issue - how do you upload billable time for an employee that is not in the same subsidiary as the project/project task? Note - this has nothing to do with user role.

Employee A in subsidiary Z has billable time that needs to be entered in NS (via csv upload) for a project belonging to subsidiary Y (a different subsidiary). The customer/project is for a different subsidiary. The employees/resources work across multiple subsidiaries but can only be assigned to one subsidiary. When we try to upload the time, we get an error "Invalid customer reference key XXXXXXXX for employee XXXX". We tried internal ID for the projects but same error. The only solution was to change the subsidiary on the employee record. We have thousands of rows and changing employee subsidiary back