Although scholars have constructed typologies of voluntary (fictive) kin, few have considered challenges and opportunities of interaction and relationships between biolegal and voluntary kin. This study focused on one type of voluntary kin, supplemental voluntary kin, relationships that often arise because of differing values, underperformed roles, or physical distance from the biolegal family, and wherein relationships are maintained with biolegal and voluntary kin. We examined how these family systems are constructed via interactions in relational triads of “linchpin” persons between biolegal family and voluntary kin. From in‐depth interviews with 36 supplemental voluntary kin, we examined themes in the linchpins' discourse surrounding the interaction, rituals, and ideal relationship between biolegal family and voluntary kin. We constructed a typology of four relational triads representing these relationships: intertwined, limited, separate, and hostile. We describe the structure and communication within each type, and implications for helping families with these triangulated voluntary kin relationships.