Decision Aid process involving many stakeholders constitute a complex situation while requires the reconciliation of multiple views, interests and preferences. Multicriteria Disaggregation—Aggregation approaches such as UTA(*) and UTA II support the estimation of additive value preference models utilizing the Decision Makers (DMs) global preferences expressed by the pre-ranking of a limited set of alternative actions evaluated on a consistent family of criteria. This research work presents the exploitation of UTA methods and voting collective functions of Social Choice Theory in order to support decision aid process in a multi-agents decision environment. Also, the RACES systems developed to support small group decision aid process, accompanying the MINORA and MIIDAS system is presented and illustrated through a real world cases study.