Hi George,
As Tom has indicated, probably the easiest way to use any other lenses would be with Hassy Bellows and Extension tubes. With adapters to fit these, you should be able to mount all kinds of large format, enlarging, and macro lenses, as well as other medium format lenses. You may want to mount enlarging and macro lenses into a large format #0 or #1 LF shutter before mounting them on the Hassy Bellows. Mounted this way the lenses will not couple with the camera except as stopped down? Through the lens metering would be possible with a metering head for the Hassy. Be aware, that with these combinations do not expect in most instances to be able to focus to infinity. It would require testing to see the extent of the focusing and magnification.
Rich