We’re running APPS 9

Is it possible to create a different document class  when loading Supplier Invoices vs. Customer Invoices using External Invoices?

We’re setting up an external integration to load supplier invoices and the documentation suggests you can only have one DocMan class for Invoices regardless of whether they are Customer Or Supplier Invoices.  We want to segregate our invoices between the two ledgers as security and roles and responsibilities are split.