While there is an abundance of literature on knowledge sharing within teams, there is a scarcity of literature on the transfer of knowledge between disparate groups where communication and coordination are difficult due to the diversity of attributes such as culture, language and priorities. The inspiration for this work comes from a project on the use of the web to enhance communication between clinicians and the families of patients in intensive care units. The paper also draws from relevant research on topics such as cross-functional teams, shared situational awareness, jointness, interagency cooperation and inter-organisational boundary- spanning. This investigation is grounded in concepts from Complexity Theory and Activity Theory and has resulted in the taxonomy of modes of knowledge sharing between disparate groups that is presented and discussed in this paper. There are five items in the taxonomy, namely Ad hoc, Spokesperson, Mediator, Embedded, Boundary Spanner. Each is described and discussed based on the research experience and an analysis of relevant literature. The motivation in presenting this taxonomy is to provide a useful tool for understanding and to stimulate a deeper and broader appreciation of this topic.