updating data

I need some help. I'm retreiving data from an access database to an excel
work***. I run a query that uses "GROUP BY" (in SQL query). Then I update
some data in the excel *** and would like to update it to Access again.

For example: I have a huge client database with "City" "Country" "Zip Code"
etc...
I run a query that groups by "City" and brings "City" and "Zip Code"
(Obviously there are a lot of clients of the same city). Then in the *** I
would have 2 fields (City and Zip code) with a lot of records. Then I update
all zip codes in Excel work***, and would like to update in the Access
Database every city's zip code (that can be repeted in many records) from the
Excel ***.

Any idea how I can do this?

thanks.

bregards

Santiago
.