Not possible. You need a physical ability to change the aperture by hand for stop-down metering. Same problem for Contax 645 glass - no way to effect stop-down.
However, Hassy Fx/Cxx lenses perform very, very nicely on a Canon or Nikon body. Mamiya M645 as well. With Hassy Cxx lenses you need to lock the lens's shutter open. Hassy can also be mounted on Leica R mount. Best adapters are Fotodiox PRO (make sure is pro, non Pro suck). I use the 110/2, mamiya 200/2.8 APO and a 150/3.5 C with great results on a 1Ds2.
