Current indicator-based sustainability assessment approaches usually have three shortcomings: (i) ecological as- pects are mostly overrepresented in relation to importance and complexity of economic and social aspects; (ii) they center on filling important gaps in scientific knowledge, but miss on utilization and implementation; and (iii) the assessment results themselves are difficult to implement in decision-making, as conflicting goals and the interaction between indicators have not been sufficiently considered. We propose an approach that fulfills systemic criteria, i.e., sufficient representation of the system including functional interaction among indicators; nor- mative criteria, i.e., considering the different value perspectives of stakeholders by including them in the process and designing sustainability ranges rather; and (iii) procedural criteria, i.e. pursuing the assessment in a true trans- disciplinary process. We present the SSP and its application for the Swiss milk value added chain. The system is de- scribed with a set of 8 ecological and 9 socio-economic indicators. The sustainability ranges were obtained through literature research and stakeholder interviews. The relationship among the indicators was elicited in a transdisciplinary workshop. The SSP program takes a geometric approach to determine the intersection space corresponding to the satisfaction of the normative ranges while taking into account the functional interactions of the indicators.