The standard MIT mailing list (i.e. firstname.lastname@example.org) does not permit moderation or address blocking.
However, another option is a Mailman list - Mailman allows for moderation, archiving, automated bounce processing, and a large number of other features. For more information on mailman, see http://web.mit.edu/lists/mailman/index.html. Please note, however, that Mailman lists cannot be used for certain features at MIT. Before transitioning your Moira list to a Mailman list, please read "What is the difference between Moira lists and Mailman lists?".
If you wish to convert your Moira list to a Mailman list, please contact email@example.com.