Use sqlldr control file to automatically create several tables in Oracle
The Utilities manual that describes SQL*Loader syntax (which no sane person can recall anyway!) has a number of case studies (doc link here). Case study 5 covers loading into multiple tables. The actual case studies are installed into $ORACLE_HOME/rdbms/demo if you choose to install the companion CD. I seem to recall that in earlier versions they were also described in full in the Utilities manual.