To split beam group at staircase

Select the Design Input | Beam Continuum tab.
Select the third beam group in the chart.
Note: The beams on grid line 6 are highlighted in the Layout view.
Right-click on the blue box labeled C17 (column 17) and select Split Group from the pop-up menu. The beam group is split into two physical members at this location.
Select the Design Input | Design Grouping tab.
Select G19 in the table or click on the newly created beam group in the Layout view.
Type -900 in the Top field for both beam segments in G19 (B14 and B15). This represents a top of beam elevation of 0.9m below the floor elevation.