This study explores stakeholder knowledge on interactions between Sustainable Development Goals (SDGs) through participatory system mapping and Causal Loop Diagrams (CLDs). We focus on SDG1/10 (reduce poverty/reduce inequality), SDG8 (decent work and economic growth), and SDG13 (climate action), aiming to make implicit mental models of SDG interactions explicit and compare them with the iSDG-AT model for Austria. A participatory workshop involving diverse stakeholders was conducted to elicit variables and dynamics underpinning five key indicators: energy poverty (SDG1/10), real GDP per capita (SDG8), work satisfaction (SDG8), total greenhouse gas (GHG) emissions (SDG13), and GHG emissions from the building sector (SDG13). The CLDs developed by the participants were digitalized, refined and connected to highlight feedback loops, synergies, and trade-offs. Results indicate that household income acts as a central variable linking multiple SDGs, with significant synergies between economic and social indicators but notable trade-offs with environmental outcomes. This paper provides insights into integrating stakeholder knowledge to support more informed policy decisions. It also establishes a shared system understanding to guide further research within the ACRP-funded SDGVisionPath project.