Scheduled ship date based on shipment priority

Hi,

Currently business is doing shipment on Saturdays for specific order which is based on Shipment priority value of 'Emergency'. Now the calendar used is having Saturdays as non working day because of which scheduled ship date is pushed to next working day and they are missing shipments at right time.

If we make the Saturdays as working day in calendar its affecting scheduling for other orders. Is there a way to achieve the scheduled ship date to default on same day for 'Emergency order's alone. We are not using ASCP.

Thanks

Ramesh