This would only work if they decided not to go with the Civil War storyline for The Avengers 3 (Kevin Feige talked about it).
He NEVER said they were doing it. He said if they were to do it the soonest it could be is in Avengers 3.
And personally, I hope they never do it. Civil War was awful. If they put it to film they may as well bury the MCU, because they're going to make the audience hate at least half of their heroes.