What I do on 3DS Max is: (kinda messy, but works)

I import the figure's OBJ into 3DS. Then I select one body part, Edit Mesh it, press CONTROL+A to select all vertexes, and type the body part name on the top bar's "Saved Selections" box. Now I press "Attach" and attach another body part, press CONTROL+I to select its vertexes and type its name on the "Saved Selections" box. Again press CONTROL+A, attach another body part, press CONTROL+I to select its vertexes, and "Saved Selections" again, until I have all the body parts I want to morph there.

Now, the fallout will cross body parts, even though the vertexes on the seams are not attached. They're just on the exact same coordinates.

After done, I "Detach" each body part using the saved selections I've previously saved. It works great, except that it's a lot of work.

Yeah... I know... I'm a mess...