Use the Multistory: Select Levels tool during stair creation to create a multistory stair on selected levels.
For example, use a selection box or press and hold Ctrl while clicking the levels. Press Shift and click a level to deselect it.
The selected levels highlight, but you will not see the stair extended until you click Finish.
The component-based stair is created and the multistory stair is generated on the selected levels.