Yes. To dive into the topic, google pictures (Sic!) For the request: "Filatov's stem flap" or "Filatov's flap on a stem".
Pictures can discourage an unprepared public;)
Shock content, but still.
! http: //mario.tomsk.fm/thumbs/h/416bf303-ad52-4787-885b-81d5240f97c4.jpg
As you can see, they have grown together. The same will happen with two fingers if they are immobilized through reparative regeneration. It is important that there is a wound surface, otherwise, of course, nothing will happen.
So yes, if you deeply damage the skin of the fingers, and then bring the edges together so that the dividing layer of the skin of one and the other finger is close to each other, then immobilize it in this position, then the skin, regenerating, will bring it together wound edges of different fingers.