how to apply different types of assign tasks for user’s methods against security groups defined in MOSS 2007.

I would like to know how to apply different types of assign tasks for user’s methods (Round Robin, Least Work, Most Work, Fastest User, Slower User, and Role Peers) against security groups defined in SharePoint 2007 without need for creating K2 roles and Smart Objects.

I would like to know if what we need is visible or NO without creating Smart Objects nor K2 Roles, we need to create only security groups in SharePoint 2007.