Hide certain custom field selections at the form level

We have custom drop-down fields that we'd like to use in our custom forms. However, we'd like to hide some of the drop-down choices in certain forms. For example, we would like a client title code field with a full list of choices available throughout the company. However, certain teams should not be able to select any but their own title codes. So we'd like to put the title code field on all teams' project custom forms, but hide all choices of that field except those that are applicable to that team.