This practical paper addresses the lack of studies on international innovation ecosystems by investigating the ‘European Network of Research and Innovation Centres and Hubs’ (ENRICH). It is currently being established in Brazil, China and the United States, as an initiative of the European Union’s Horizon 2020 research and innovation programme. Focus within this paper is on ENRICH in Brazil, which aims to become the main hub and contact point for European and Brazilian Science, Technology and Innovation (STI) actors. Among the many aspects to be determined in this context, this research aims to address the question on ‘how to design a tool that supports STI actors to become involved in ENRICH in Brazil?’ A member-decision-support tool (MEDESU) is designed for STI actors in Europe and Brazil. From the various decision support systems (DSS), we find that a knowledge-driven DSS is the most suitable type of DSS for our MEDESU which is built based on a decision-tree that we created. Its structure consists of different question-paths which result in the proposition of the most suitable ENRICH membership type, respective of the users’ responses. The paper presents the design of a MEDESU to attract and support European and Brazilian STI actors to become part in the ENRICH community and to simply membership selection. ENRICH in Brazil is a unique international innovation ecosystem which is currently being built and requires suitable tools for the creation of its ENRICH Community. The MEDESU developed and presented in this paper is to attract, retain and engage with European and Brazilian STI actors. The next step in the DSS development is its testing and refinement before implementation in the ENRICH in Brazil community website. Apart from the implications for innovation practitioners who might use the tool, the insights from its development can be of relevance for policy makers that are looking to establish international innovation ecosystems, as well as for scholars who are interested in the international dimension of innovation ecosystems and the design of roles and strategic partnerships across continents.