You could try to rebuildsurfaces function so they have the same number of isoparms around the edge to join, and then stitch. Thats what I'd try, though I'm no expert. To attach use nurbs component display>surface origins to check they're the same . You may have to detach a fair bit of your two objects, and rebuild their surfaces to stitch and attach it all together nicely. Its kind of like a surreal cross between the towers of hanoi puzzle and a 3D slide puzzle.