You could copy it into two parts and cut away opposit halves of each one. Then copy both halves into another part in the right position. You have to tie one of the copies into a coordinate system that puts it into the right position. Then do whatever you need to smooth the hinge part out. This should update if you make any changes to the original model if you do it all in ordered. Not very elegant but it would get you there. Hopefully someone has a better answer!
I apologize for language, but you can see the steps to repoduce and attached your finished models (ST6).