This paper presents the “Interactive Groups”, the form of student grouping that INCLUD-ED has found to be most successful. IG is contrary to any kind of segregation of minority students, which has been widely proved to reproduce these students’ school failure and exclusion. Instead, IGs draw upon cultural diversity to achieve success for all. They include people from the community, usually from different cultural backgrounds, to attend all students in small groups in the same classroom. Two case studies of pre-primary and primary urban schools in Spain that organize their classrooms into IGs were conducted. Both schools showed school success, were located in low SES areas, served minority students, and had strong community involvement. The analysis of quantitative and qualitative data showed that: a) participants perceived that IGs improve academic achievement. These perceptions are consistent with the results of these schools in external evaluations; b) the IGs also improve intercultural coexistence through promoting democratic values and solidarity; c) the community volunteers who participate in the groups, from diverse cultures and often with no academic profile, are crucial in supporting the aforementioned results. This paper extends knowledge on classroom interventions that foster social justice in education and alter intercultural power relations.