Zones are not intelligent enough currently to be multi-story zones.
I would probably place two Zone elements, one for each story. Then I would set their height values so that they touch vertically. Also I would set the same Zone Number for both.
Loving Archicad since 1995 - Find Archicad Tips at x.com/laszlonagy
AMD Ryzen9 5900X CPU, 64 GB RAM 3600 MHz, Nvidia GTX 1060 6GB, 500 GB NVMe SSD
2x28" (2560x1440), Windows 10 PRO ENG, Ac20-Ac28