Hide/shadow A Framework Method?

I would like to make sure that certain properties/methods of native framework methods are not called in a project I'm working on. I want to use custom methods instead, and make sure that those methods are always used. How would I do that?

These are the details:

In a rather large web project, we have several pieces of code creating and sending email messages using the MailMessage object. I want to perform some additional checking, logging etc whenever an email address is added to either the To, CC or BCC MailAddressCollection
of a MailMessage object. Basically I'd like to make sure that it is not possible, in this entire Solution, to do this: MyMailObject.To.Add(something@somwhere.com), and the same for "CC" and "BCC".

First, I thought about not using the MailMessage object at all, but inherit it and override the methods that allow adding of addresses. I ran into some trouble though when trying to shadow the "To" property, since "To" is a reserved word... And then I realized that it probably wouldn't solve my problem entirely anyway, since there would be nothing stopping another developer (or myself being stupid) from creating an instance of the original MailMessage class and use it at will.

I have successfully created a method which centralizes all the adding of various recipient addresses, but I can't figure out how to prevent the original methods from being used by mistake.