If the span is only 14' why can't you twin the existing beam ...so each beam holds only one side of the floor load ...I am assuming by hidden beam you mean the joists are butted up to the beam... pick the easiest side ... shore up the floor joists and cut them short....nail and laminate the new members on to the existing beam ...use joist hangers to reattach joists ...remove temp shoring wall and nuisance post