一个定语从句前如果有二个名词，定语从句修饰哪个名词是需要根据逻辑判断的。所以你这个句子要做出判断，你得知道a Procrustean bed是什么意思，而不是乱猜。下面是词典对a Procrustean bed的解释：
a Procrustean bed：something designed to produce conformity by unnatural or violent means.
In Greek mythology, Procrustes was a robber who tied his victims to a bed, either stretching or cutting off their legs in order to to make them fit it.
了解了a Procrustean bed的意义之后，结合定语从句的意义，你就很容易地知道定语从句其实是解释a Procrustean bed的，所以定语从句的先行词是a Procrustean bed。
