Wind Loads on Long Wall of Steel Building

I am an engineering student focusing on structural engineering. For a design project this year, my group and I designed a very standard rectangular structural steel building (12 meters high, wide flange columns along the perimeter, one row of columns in the center, open web steel joists, braced bays, etc.). I have attached a sketch for reference. One thing that I had a hard time wrapping my head around was the fact that the wind acting on the long wall was assumed to be perfectly distributed to the short walls (i.e., each short wall takes half the wind load).

If I was to design a rectangular building in which the long wall was much longer than the short wall, would I assume that the entire wind load acting on the surface of the long wall would be evenly distributed to the short walls as well? I have attached a sketch for reference. I know that in wood construction, you can design partition walls that are perpendicular to the long wall as shear walls to take the wind load. In large structural steel buildings, they are often open-concept with no interior partitions or frames. How would you handle wind loads acting on the long wall in this type of situation?

I appreciate any responses even though this may seem basic to some.

Thank you.