Cell cortex contraction is key for shaping cells, enabling movement, division, and response to mechanical signals—essential for multicellular life. Differential membrane contractions between cells strongly affect segregation. We introduce a model of active particle rings interacting through differential contraction, demonstrating that segregation emerges from this process, with ring dynamics acting as an effective temperature. The interface decay exponent, is -1/3, differs from prior cluster fusion/diffusion model predictions.