The flexibility potential of decentralised energy resources in the distribution grid raises not only the question of how flexibility will be coordinated between grid operators, but also which role aggregators will have in coordinating flexibility. Aggregators can incentivise customers to provide flexibility, by offering this flexibility in markets or to different service users. However, the aggregated resources (e.g. electric vehicles, photovoltaic systems, battery storage system), possible services (e.g. constraint management, access to wholesale markets or balancing services), service users (e.g. grid operator, balance responsible party) and optimisation goals (e.g. self-sufficiency, sustainability, costs or promotion of communities) can vary, resulting in heterogeneity of aggregators. The European Union also strengthens the role of aggregators in their directive, thus facilitating multiple aggregators for one customer. However, the coordination in a digitalised power system lacks a suitable framework to unfold their full potential. Thus, this project aims to solve the research question: ”How can heterogeneous aggregator types be coordinated in a digitalised power system?"