We have the same situation on our report.. only two cars, but four car loans reporting.
The first car, we refi'd with our CU within 3 weeks of purchase. Both show, with the original loan showing PIF.
The second car was financed through a company that would bought out by Americredit after about 5 months. Both show on that, too, with the original showing PIF.
As I understand, as long as the original loan shows $0 bal, and the second loan has the original open date of the first loan, it's fine.