Duplicate your surface material.
Give the second surface material a slightly different name.
Then apply one material to one window and the second material to the adjacent window.
They will look the same in 3D (because they are) but will not blend as technically they are different materials.
One of the forum moderators.
Versions 6.5 to 25
Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10
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