Hello,
I assume the scope of this project is to split the current data and not to develop a system which will take care of this with other spreadsheets as well. Please confirm. If my understanding is correct, I will be happy to implement this for you.
I'll transfer your data to MS Access and use ASP script to generate the files. I'll be happy to share the script and MS Access table and the steps I did to generate the files. Does that make sense?
Best regards,
Swagata