Use the :memberof match-type tag to determine if a sender or host is on a particular PureMessage list. Lists are enclosed in quotes when passed as arguments with the :memberof match-type tag.

Policy Script Example:
if envelope :memberof "From" "whitelisted-senders" {

In this example, the match-type :memberof takes a PureMessage "whitelisted-senders" list as an argument. If the message sender is matched with a sender on this PureMessage list, the message is delivered to the envelope recipient.