Lists are used to configure domains or addresses that should be treated differently within a policy rule. For example, in the default PureMessage policy, the first rule checks the message relay against the relays configured in the Internal Hosts list.
To handle messages differently for members in each list, add a new list, and then apply it within the policy script. For example, to create a list of users who receive spam headers for messages with a spam rating of 50% or more, build a custom list (or use an existing list), and then create a rule that adds a header only if the recipient is a member of the list.
Some message characteristics, such as "Recipient's address" and "Envelope to", provide the option of using the match operators "Is a member of" and "Is not a member of" to compare the message characteristic with items in a specified list. Once the new list is created, it becomes available for selection in a Policy Constructor drop-down list that is displayed when you are configuring a test that includes the "Is a member of" or "Is not a member of" match operator.