Correct me if I am wrong, but I understand that loan participations would be treated in a similar manner to loans that are sold on the secondary market - and therefore exempt from the Privacy opt-out and prohibitions on information sharing under FCRA.
It is part of the actual servicing of a transaction initiated by the consumer.
Now, if the participation is for a business loan, hopefully you have the authorization in file from the principals to have run their consumer credit reports.