There are many theories concerned with inter-persoanl communication. The most relevant one is GROUPTHINK by Irving Janis (1972), which discusses how groups are formed in organizations. Than there is LANGUAGE EXPECTANCY THEORY by Burgoon (1995) which discusses cultural and sociological norms and preferences over the communication process.
Than there is INTERPRETATIVE AND INTERACTION THEORY by Watzlawick (1974), COORDINATED MANAGEMENT OF MEANING by Pearce and Cronen (1980) and FACE-NEGOTIATION THEORY by Stella Ting-Toomey (1993) all of which are about the various facets of the communication process and all the factors which influence it.
You also could find very interesting specialized points on group dynamics in Irvin D. Yalom' book: The Theory and Practice of Group Psychotherapy. Basic Books, 2005
Jacket: "The authors present the latest research and clinical guidelines on group psychotherapy and explore the most recent developments in the field, drawing on nearly a decade of new research as well as their own broad clinical wisdom and experience. This edition features new sections on brief group therapy, online therapy groups, ethnocultural diversity, trauma, managed care, and specialized and structured groups (addictions and groups for the medically ill), as well as updated references and new clinical vignettes drawn from the authors' recent practice."
You also can find a lot of very interesting books in the Tavistock Clinic Series :
http://www.karnacbooks.com/SeriesDetail.asp?SID=10 on group dynamics, organizations as complex groups, conscious ans unconscious communication,...
Poole, S., Poole, M. S., & Hollingshead, A. B. (Eds.). (2004). Theories of small groups: Interdisciplinary perspectives. Sage Publications.
Theories of Small Groups: Interdisciplinary Perspectives brings together the threads that unify the field of group research. The book is designed to define and describe theoretical perspectives on groups and to highlight select research findings within those perspectives. In this text, editors Marshall Scott Poole and Andrea B. Hollingshead capitalize on the theoretical advances made over the last fifty years by integrating models and theories of small groups into a set of nine general theoretical perspectives. Theories of Small Groups is the first book to assess, synthesize, integrate, and evaluate the body of theory and research on small groups across disciplinary boundaries.