File to File Scenario (File splitting)

Experts,

I am working on B2B scenario. I have a source purchase order flat file with multiple orders in it I want to converted that into EDI file and create individual file for each purchase order.

I am able to convert he file however i want to know how to split the files or create individual files. Do i have to write any java function for that?

eg.

Sourcefile

Order1, Vendor, date

Order1,Vendor, Line1

Order1,Vendor, Line2

Order2,Vendor, date

Order2,Vendor, Line1

Order2,Vendor,Line2

Order2,Vendor,Line3

Expected output

File1

Order1, Vendor, date

Order1,Vendor, Line1

Order1,Vendor, Line2

File2

Order2,Vendor, date

Order2,Vendor, Line1

Order2,Vendor,Line2

Order2,Vendor,Line3

Thanks,

Nishant