How to Derive Tax Area on Time Entry from a Work Address

We have a requirement for US Tax Area to be determined based on Work Location at the TIME ENTRY level. The workers entering time will know the address where the work was performed, but may not know what Tax Area this is. A worker may work in multiple counties/states in one day (so this cannot be configured at EE Master level). We have multiple valid Tax Areas for one Business Unit (so this cannot be configured at BU Level).

Has anyone else solved for this? A worker travelling across, and working in, multiple US tax areas in one day?