With the "Transparent Story"  feature in the  Settings section of the  menu , you can set whether the architectural and structural objects on the upper and lower stories will be visible on the active story, as well as with which line types the view will be made.

You can complete your drawings by catching the nodes of the guide lines and referencing the lower or upper floors.

For example; You can draw your beams seeing the walls of the lower story while in the lower story plan, or you can see the structural plan mode in the architectural story plan and direct your designs accordingly.