In line with the shift toward dementia-friendly communities, HCI research is increasingly exploring holistic ways to support people living with dementia as active community members. However, less is known about how existing community networks influence technology design and effectiveness. This paper analyses Community-Based Participatory Design (CBPD) workshops conducted with individuals living with dementia, their spouses, and program coordinators through Wenger’s Communities of Practice Framework. We demonstrate how participants’ interactions created a community of practice through their: engagement in creating mutual meaning, alignment around a common purpose, and imagination in envisioning new possibilities for inclusion. Our findings highlight the agency of participants as they worked to create inclusive experiences for themselves and others. Our findings additionally demonstrated how community boundaries create systemic barriers that lead to non-participation. We argue Wenger’s framework offers a roadmap for designing technologies that foster person-to-person interdependence, helping to build more genuinely inclusive communities.