A museum visit is often a collaborative activity with many people visiting the museum with family or friends. However, mobile museum guides often separate the group rather than enhance group interaction. As part of our efforts to support group activity in the museum we introduce a novel museum visit planning system that enables small groups of visitors to collaboratively plan their visit. After individual planning from home, a group of visitors can re-plan their visit as needed to accommodate for changes due to group preferences or environmental constraints. Visitors use a handheld device, also used as a museum visitors' guide, to interact with a situated display located at the entrance of the museum. We describe the system and discuss some of the design challenges we had of designing a groupware system in a public space such as a museum.