Your requirements are antithetical to each other. If you need to make marketplace payments, look at Amazon's Simple Payments (used by KickStarter amongst others) which prevents either of the end parties from knowledge of each other, but does not prevent Amazon from knowing about them.
PCI compliance should be trivial for any functional payments provider.
Somebody has to take the responsibility for the collected money and in this case it has to be you if you want to make it anonymous. You can consolidate from lot of payers and distribute to the receivers.
PCI compliance should be trivial for any functional payments provider.