I want to use a list (column B) to restrict data entries into a spreadsheet.
However, I want the list to return a value in a different column (column A).
For example:

BH Borehole
AR Air

I would like the list to show the real-world names, but the data that is
entered into the cell to be the associated code. This is a DB interface
tool, for an existing database with specific fields already setup, so I
cannot add columns.

Thanks!