Drop down combo box in form

[Guest]

I am trying to make a combo box (based on a table) for a
list of rates based on the state and county the client is
in. The only thing in the rate table is the county,
state, and rate. However the client table does not have a
county but a city. All I want to do to provide for the
form is the list of rate by county,state with the rate
being stored into the text(combobox). It does not tie(or
link) to anyother tables in the database?????? Does it
have to??? Do I have to retype the whole table as list
values or how could I just grab the list to show it and
use it????

Please help,
Tom