I have an Excel file of about 10,000 lines with the following format:

OriginCity OriginState DestCity DestCountry Cost1 Cost2

NY NY Vigo Spain 110
24
NY NY Vigo Spain 110
36
LA CA Hamburg Germany 245 23
LA CA Hamburg Germany 245
23

I need to create another Excel file for each Origin-Dest combination, but I
only need the value from the Cost1 column once and add the Cost2 columns
together. So the new lines should look like:

OriginCity OriginState DestCity DestCountry Cost1 Cost2

NY NY Vigo Spain 110
60
LA CA Hamburg Germany 245 46