Ability to validate by PO or something similar to Dispatch Orders, but with letters on Touch Screen Kiosks

We have the need to allow a driver to enter in a Purchase Order Number or a Validated Code that will then link to a Dispatch Order. This could be a one to one or a Many to one relationship. The issue at hand is we need a driver to enter a string that has letters and numbers into the kiosk and for it to find their assignment. The Dispatch number won't work because it is an INT in the database. And the Assign Vehicles screen, Id Authorization screen, and basic select lists won't allow for Validation of that PO/Validation number against a predefined list of Hauler, Customer, Product, etc..