Objective: This study analyzes communication and inclusive community engagement in FOSIL BKM Medan and develops an initial communication model for mosque networks in a multicultural society. Theoretical framework: The study draws on participatory communication, social capital, collaborative governance, and symbolic interaction to explain relationships between dialogue, trust, collective action, and organizational meaning. Literature review: Previous studies address religious volunteering, community empowerment, and collaboration. The remaining question concerns how relational closeness becomes traceable decisions and coordinated action across mosque organizations while accommodating different community perspectives. Methods: A qualitative single-case approach uses participant observation, in-depth interviews, focus group discussions, and organizational document analysis. Interview excerpts from Informants support thematic interpretation. Analysis involves data condensation, presentation, verification, and pattern matching, distinguishing reported practices from normative policy proposals. Results: The accounts identify silaturahim as relational capital and emphasize documented follow-up, responses to aspirations, transparent commitments, and complementary digital and direct communication. These themes inform seven CECMN components: needs and asset mapping, structured dialogue, joint planning, collaborative implementation, network strengthening, hybrid communication, and participatory evaluation. Four propositions connect voice with influence, trust with commitment, networks with resources, and experience with learning. Implications: The model offers guidance for inclusive dialogue, responsibility allocation, and shared learning within Medan’s culturally plural setting. North Sumatran relational traditions provide contextual insights without establishing interethnic or interfaith outcomes. Implementation testing remains necessary. Novelty: The contribution is a context-specific integration of relational communication mechanisms and governance supports in the Community Engagement Communication Model for Mosque Network.