Allocation of goal responsibilities to agent roles in Multi-Agent Systems (MAS) influence the degree to which these systems satisfy nonfunctional requirements. This paper proposes a systematic approach that starts from nonfunctional requirements identification and moves towards agent role definition guided by the degree of nonfunctional requirements satisfaction. The approach relies on goal-dependencies to allow potential MAS vulnerabilities to be studied. In contrast to related work where organizational patterns are imposed on MAS, roles are constructed first, allowing MAS organizational structures to emerge from role definitions.