Importing data into a Multi-select Text Field

This is more of an Excel rather than Quickbase question.

I want to update a Multi-select Text Field for hundreds of Quickbase records from 8 .csv files

The .csv files contain just two columns, Customer ID (key field) and Group, like the examples below.

flooring.csv
Cust ID        Group
A123            Flooring
B123            Flooring
C123            Flooring

roofing.csv
Cust ID     Group
A123          Roofing
B123          Roofing
C123         Roofing

carpeting.csv
Cust ID     Group
A123          Carpeting
B123          Carpeting
C123         Carpeting

Is there a way for Excel (or an Excel add-on) to Merge data from two or more .csv files so that I end up with the example below that I can then import into the Multi-select Text field in Quickbase?
Cust ID        Group
A123            Flooring; Roofing; Carpeting
B123            Flooring; Roofing; Carpeting
C123            Flooring; Roofing; Carpeting

Thanks, 

Jim