Multiple-person decision making (MPDM) considers individual ideas with respect to several criteria. One difficult point is how to aggregate ideas from Decision Makers (DM) of diverse backgrounds without information loss. This paper describes a synergistic methodology using three existing decision making methods (AHP, Ideal Value method and Trust Matrices). The new methodology examines the trustworthiness of each DM with respect to professional skills, gender, and non-professional aspects; then, goes further regarding each attribute. By combining AHP, Ideal Value method and Trust Matrices the new methodology can minimize information loss, which happens frequently in traditional MPDM methods, and better represents the true opinions of decision makers with less bias. Finally, a case study will show how to apply this new approach.