Unlimited A-3 occupancy

[walker.t]

with a party wall (2 Hour Fire Wall)

Your image is an image from the IBC Illustrated Handbook with modified text and does [edit: meant to say "does not"] show a party wall configuration because there is no lot line under the party wall. The original image does not call out a fire wall so the image is addressing a single building.

2021 IBC 706.1.1 Party Walls (partial quote, emphasis added)
Any wall located on a lot line between adjacent buildings, which is used or adapted for joint service between the two buildings, shall be constructed as a fire wall…

Whether or not it is truly a party wall, only three sides of each of the individual buildings has open space, therefore the building does not qualify as an unlimited area building.