Selecting Form Numbers

Hi! I'm trying to create a form where our sales team allocates a series of codes (Form Numbers) to our customers. For example:

1) Sales guy goes to customer 1. He allocates code 001 and code 002.

2) Sales guy goes to the next customer 2. He allocates code 003, 004 and 005

However, i need to work so that once the code has been allocated to a customer through a form, that code is no longer available as a selection for the next customer. This is so that there is no duplication of codes during submission as each code should be used only once.

Is this possible in Canvas?