This is a comprehensive report of a study of the mechanisms by which the family regulates its interaction with the immediate social environment. Subjects were four multiple family groups, each composed of six or more families, meeting in both hospital and home settings. In each family, at least one member was either an alcoholic or an adolescent with behavioral problems. The authors include descriptions of each group and its dominant characteristics. Data is based primarily on observations of group interaction, attendance patterns and sociometric questionnaires. A crucial question is whether the multiple family group duplicates, in any meaningful way, the social process of everyday social settings. The results suggest that "community-like" processes do develop spontaneously in multiple family groups. These include the differentiation of these groups into subgroups (often peer groups), social stratification (particularly along dimensions of power, prestige and conspicuousness) and phenomena related to the family's first entry into and final departure from the group. Findings also indicate the potential usefulness of the multiple family group as an observational setting as well as modifications still required of the model. (Author/DOW)