This paper describes four cases of intervention in the relations between groups of widely differing social status and power. "Dialogs" between high corporate executives and social activities from urban poverty areas in three cities were supported by a foundation interested in promoting long term cooperation between the groups on social projects of benefit to the cities involved. The outcomes of the four cases are examined for theoretical implications for the third party intervention to improve such vertical intergroup relations. Four general thrusts of third party activity are discussed: (1) diffusing the impact of power asymmetries, (2) managing boundaries and organizing premises, (3) influencing interaction patterns, and (4) institutionalizing change. (Author)