Forbid a specific combinations of Configurable Product attributes.
For a simplified example, consider shirts with designs (4 possibilities), colours (3 possibilities) and sizes (3 possibilities). That would be 36 combinations. But the Red Apple design looks horrible on red shirts so we would want to disallow that combination and create only 33 shirts.
In this simplified example, it would make sense to just create all the examples and then remove the 3 unwanted shirts. But the real example is 7 attributes with a bit over 2000 possible combinations - of which only 600 are wanted. Narrowing down over a thousand products to remove, or individually creating 600 products, is not feasible.
How can an admin create an array of simple products used as Configurations in a Configurable Product, but forbid specific attribute combinations?