dynamic distribution group

A distribution group that uses recipient filters and conditions to derive its membership at the time the message is sent. For example, a dynamic distribution group might specify a recipient filter such as "users with external e-mail addresses and contacts with external e-mail addresses", and a condition such as "Recipient is in a company". When someone sends a message to this dynamic distribution group, Exchange queries Active Directory for all recipients that match the filter and conditions specified. Then Exchange returns a list of all external recipients that work for the company specified and sends the e-mail message to that list of recipients. [Exchange 2007]