Focus group research reflects content contributed by participants and the influence of interactions among participants. Analysis of interactions provides insights into focus group dynamics and the contextual meaning of focus group topics. The aim of this report is to analyse interactions that establish or protect a common ground in focus groups of family members caring for adults with Huntington disease (HD). HD tends to stigmatise persons with the disease, as well as their families. Thus, many of the topics in these groups were sensitive. Establishing a common ground was of paramount importance to group members. Participants used interactional processes that combined validations and challenges across assertions of knowledge or expertise, and disclosure of personally painful or socially sanctioned thoughts or feelings. Participants couched their contributions in ways that established similarity with others and when disagreements arose, group members developed processes to sustain their common ground. These behaviours served to facilitate group solidarity and may have influenced the information provided by group members. Awareness of interactions to facilitate maintenance of a common ground allows leaders to recognise the importance of such interactions for the group's functioning, and provides insights for researchers into meanings of focus group findings.