Does a divorce take effect when a husband tells his wife: "Inform her that she is divorced"?

It appears that a man's statement to his wife's family, "Tell her she is divorced," effectuates the divorce the moment it is uttered, regardless of whether the news reaches the wife or not. This is the view held by Al-Sarakhsi, Ibn Nujaym, and Malik. Some scholars are of the opinion that if the husband intends by the word "divorced" to inform of a previous divorce, then no divorce occurs by it. However, the first opinion is stronger, and Ahmad explicitly stated that this wording is clear and effectuates divorce.