Amid a global pandemic and the looming climate crisis, there is an increasing need to understand how to promote largescale, coordinated action between different groups. Yet certain factors – such as inequality between groups – can hinder cooperation. We aimed to establish how to orient groups towards a superordinate goal when they have unequal resources. Participants were divided into two ‘countries’ and asked to assemble Lego into food (by building pieces in a certain order) to prevent starvation amongst ‘the people’. One ‘country’ had few pieces of Lego whereas the other had an abundance, and the only way to maximise food creation was for the groups to work together. We assessed the efficacy of three diverse interventions on superordinate behavior and attitudes: compassion meditation training (Study 1), lower inequality (Study 2), and the introduction of a pro-sharing group norm by a confederate (Study 3). Compassion meditation training and altering the degree of inequality between groups did not have a clear effect on collaborative action. Instead, only the introduction of a pro-sharing group norm resulted in enhanced sharing behavior, made participants feel more cooperative and reduced fears of being compassionate towards others. Our findings speak to the importance of leadership in promoting coordinated action to address challenges that face the superordinate group.