Socializing and interaction are important aspects for families who visit museums. Mixed reality (MR) uses a set of technologies that museums employ to encourage this behavior, but they face challenges in maintaining family cohesion with experiences across different exhibitions and kiosks. In this paper, we explore these challenges broadly to provide strategies for MR exhibitions that support better family cohesion, and thus interaction. As part of our exploration, we partnered with the Indianapolis Children's Museum and used its "Take Me To Greece" exhibition and observed intergenerational family interactions at eight different kiosks with a range of MR technologies using "research in the wild" approach. We present our findings in terms of concerted immersion patterns of families with the kiosks encompassing both real and virtual spaces, while disrupted interactions when family members split from the group to interact with virtual kiosks. We then present design considerations to provide a broad understanding of the aspects of reality and virtuality in a MR children's museum exhibition, and the influence of these MR dimensions on intergenerational family interactions.