If you want to avoid copy & paste into the new CSV-generating XLS, then open
each original CSV file, immediately save under a dummy filename, e.g.,

C:\Windows\Temp\foobar.CSV

Then open your XLS file in which you would have changed all file references
from <whatever to C:\Windows\Temp\[foobar.CSV]. Generate the new CSV file,
close both files WITHOUT SAVING EITHER, and repeat the process with the next
original CSV file. You could use another XLS file with macros to automate
this process.