A metallosupramolecular prismatic nanocage with altogether six reactive aldehyde terminals was utilized as a sophisticated "monomer" in a template-directed constitutional dynamic imine polymerization to prepare an unprecedented triple-stranded dynamer. To analyze the correlated growth in its three congener strands, a fully covalent triple-armed star polymer was fabricated from the metallodynamer through capping, imine reduction, and removal of the template. Atomic force microscopy analysis of 68 triple-armed star polymer molecules suggests that the growth of their arms is correlated to similar to 72%.