"Exploit our schools' diversity to enhance training with UDEL21" is a French speaking Belgian consortium that gathers representatives from the Catholic Secondary Education Federation and SeGEC’s Study Office with 3 schools of the same network. The Institut Saint-Jean-Baptiste from Saint-Gilles and CS Notre-Dame de la Sagesse from Ganshoren are two schools that have already been exploiting diversity for years, under the angles of multiculturality, multilingualism and adapted methodologies. The Institut Notre-Dame de Joie is a specialized school - dedicated to girls with special needs of the 3rd form, that will add the "inclusion" dimension to diversity. The three Brussels schools are an ideal reference to help SeGEC to reach its objectives of quality, learning organization and professional development of the education staffs of its school communities facing the diversity challenge. This one, amplified by the dramatic actuality of the refugees escaping from their countries in war, reinforces the idea that we must implement new strategies to help our staffs reaching the aim!Engaged in a European Strategic partnership with Flanders, Austria, Slovenja, Italy and Czech Republic - UDEL21 = Use Diversity to enhance Learning for the 21st century – SeGEC wishes to enrich the training modules that will be the Intellectual Outputs of this project with the daily experiences of the three schools. Gathering them with the SeGEC delegates to coordinate the consortium and associate them to the international mobility sessions should improve each participant humanistic, linguistic and pedagogical competences. The impact, for themselves and their institution, will still be more important thanks to the fact that schools from every partner country, and others, should take part to UDEL21 international conferences and courses. Afterwards, SeGEC will disseminate these trainings among its schools through its own in-service training program throughout Belgium but also by promoting the European courses that will be proposed after the project.