That should be possible with SOL #231 and some classification work.
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In this quick example the Slab has 9m^2 in a 16m^2 space.
The condition is that the Slab in the same space should be at least > than 90% of the Space Area (which would be the 14,4 m^2). In you case it would then e.g. be <= 0.3 I guess.
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