Flocks of birds and schools of fish are delightful and awe-inspiring examples of collective motion that we see in nature, where groups of individuals, each possessing only limited, local information, nevertheless come together and display coordinated motion. This phenomenon also extends to much smaller scales, as in migrating clusters of cells that mediate physiological processes such as embryonic development, wound healing and cancer metastasis. In this talk, I shall describe our work on modeling such clusters, highlighting how frustration can arise at the group level because of heterogeneity in behavior among members of the cluster. I shall show how this frustration can be resolved leading to new collective phases of motion that are experimentally observed in malignant lymphocyte clusters and can be functionally important – enabling robust chemotaxis and “load sharing” among cells.