As of the Fall 2007 release, actions that are defined via the Actions Wizard support SharePoint Groups. When an action is defined or executed, both “All Users” and “SharePoint Group” are respected when referencing a “Person or Group” column data type, such as Assigned To or CC.
For example, say a user creates a SharePoint group called “My Team” which only contains individuals from a particular team. An Assigned To column is set to reference the My Team group. When an action definition is created via the Actions Wizard and a list is referenced that includes the Assigned To column, the drop-down in the Actions Wizard will only display the names of the people in the “My Team” group, not “All Users.”