I'd suggest a shell script that would fire off a SQL*Loader process for each of the different file layouts.

From documentation on SQL*Loader:

To load data from multiple datafiles in one SQL*Loader run, use an INFILE clause for each datafile. Datafiles need not have the same file processing options, although the layout of the records must be identical.

Write a control file for each of the 5 or 6 different data file layouts then make sure to reference that in your calling statement.