SD7 is currently not able to put more than one flight on a single landing. The only possibility is to draw a stair with the landing and 1 flight and make another flight as a second stair and have the parts corrected with a cad program.
I have a job requiring a symmetrical stairs with 90 degree winders at the bottom, with both stairs converging on the same quarter landing, with a shared final 2 tread flight.