My son-in-law and I would like to remove a 3′ wide window in his brick house, enlarge the opening and install  6′ French Doors with 1.5′ wide sidelights on each side of the door.  The doors will allow access to a newly constructed deck.  A steel lintel exists above the original 3′ wide window.  The interior ceiling joists run parallel to the exterior wall so we are wondering about the need to build a temporary stud wall to support the ceiling.  In addition, we are concerned about the best way to support the brick wall on the exterior while we open the wall and install a new header, studs, doors and sidelights.  Should we order a new lintel that extends the entire length of the opening or three separate lentils over each opening i.e. the French doors and the two sidelights?