If you hold enough portions to total say $500 dollars AND the borrower is in default then prosper should release the information the borrower provided to prosper to you so that you can persue collections yourself for the portions that you hold.
Since this is something that would cause a borrower to repay money to a lender, Prosper would raise all kinds of privacy concerns and worry the collector might infract the FDCPA (the law that says you can't break kneecaps and so forth).
Prosper doesn't bat an eye about breaching contracts with lenders or selling unlicensed securities, but when it come to any infraction of a deadbeat's privacy, Prosper is vigilant.