This paper describes the results of the use of a Group Support System (GSS) and two "hindcasting" scenario exercises. The GSS is used to implement the hindcasting, knowledge mapping, and knowledge representation techniques as disaster planning tools. This work improves our understanding of the knowledge engineering process in the areas of knowledge acquisition, validation, and representation when the knowledge must be collected from the multiple experts, and transferred to a knowledge base. The experiences from the exercises illustrate how the collection of the knowledge of experts may be supported by a GSS when the experts perceive their task to be one of collaboratively deducing a rational causal explanation for a complex event. The results indicate that managers may improve their ability to integrate multiple expert's knowledge into the disaster preparedness planning process using GSS processing techniques.