Inventory Distribution - Serial Number Duplication on Shipped Out Inventory

Does anyone have experience with inventory distributions using serial numbers with a mask? 

ISSUE: Serial numbers used for inventory that has not yet been shipped out does not allow reuse and displays a message to notify the user, but if the inventory quantity associated with the serial number is shipped out of the system then it allows distribution using that serial number. Our products must all have unique serial numbers and it is leading to duplication.

GOAL: Restrict any and all duplication of a serial number associated with each item so that it may never be reused while in inventory and after it has been shipped out.

Any insight on how to set this up would be very appreciated as it does seem strange that duplication would ever be allowed.

Thanks in advance!