In this paper, the authors address the problem of modeling collaborative decision and knowledge intensive business processes (sometimes referred to as Decision Intensive Processes or DIP processes). DIP processes assist users in performing decision intensive tasks, and provide users with guidance relevant to process execution context. DIP processes are by nature collaborative, data-driven, need to support various kinds of flexibility at design and run time, and need to integrate with external services and information sources. Such a combination presents significant challenges for contemporary business processes technologies. They present a solution based on a business artifacts paradigm (a.k.a. business entities with lifecycles) using a Guard-Stage-Milestone (GSM) model for declarative lifecycles specification.