Research on senior leadership in higher education systems is urgently needed, particularly in the context of system-wide transformations. This study focuses on a critical juncture in Ireland, during which Institutes of Technology (IoTs) collaborated to undergo 'redesignation' as Technological Universities (TUs). Based on interviews with the fourteen presidents of the IoTs, this research employs the Community of Practice framework to analyse their interactions, strategies, and approaches to a policy-initiated, systemic change. Despite decades of pervasive competition, these senior leaders formed a community of practice as they worked collectively to achieve the common goal of TU status. Four key themes emerged: "Embracing a more expansive external role;" "Acknowledging obstacles to collective leadership;" "Forming groups, collaborating and competing;" and "Leading calmly and fostering unity." The findings of this study advance our understanding of three interconnected fields: senior leadership practices in higher education, the interplay of collaboration and competition in higher education; and the facilitation of policy-induced systemic change within higher education systems. Our findings have significant implications for institutional leaders, policymakers and scholars aiming to comprehend and improve leadership practices in higher education.