The H2020 project “EOSC Pillar” and its three “sister projects” (5b Projects) are an excellent example of how different European projects can effectively participate in the EOSC building process united in a serious, determined effort formalized by a consensual agreement between the projects. The regional approach, responding to individual, regional needs, has demonstrated the importance of jointly addressing challenges related to the European Open Science Cloud in order to reach the diverse and fragmented European research infrastructure landscape. The resulting FAIR data and conclusions are essential building blocks for continuing similar efforts.