Outlook rules - is there a way to prevent e-mails with defined content from sending? - Office 365

We very occasionally have circumstances at our office where we wish to ensure that particular content, such as an address, is not inadvertently sent to a particular recipient. It is easy enough to set up a custom rule at individual machine level which will specify the recipient and the content, but the only consequence that comes close to preventing sending is for the send to be "deferred" by a specified time. Which is not that useful, particularly as I am not sure where that deferred e-mails sits and there is no prompt to tell us that it has been withheld.
Does anyone have any suggestions for how I can achieve this?