Build field name with data from a file record

I have an extract table with fields that are named for the combination of data that the amount is a total for each combination (state/county/city).

File: BalanceDataFile

Fields: NY_Rockland_Nanuet_totalamount, NJ_Bergen_Paramus_total amount, VA_PrinceWilliam_Reston_totalamount, et al

Can I take the values read from different files and concatenate each value to form a string in C# that I can use to reference the field and assign an amount on the extract table?

e.g. the state = NY from the State file; county = Rockland from the County file; and Nanuet from the City file to form the string "NY_Rockland_Nanuet_totalamount".