Abstract: All phases of emergency management activities – that we will reference hereafter as eResponse activities – depend on data from a variety of sources and involve a range of different organizations and teams at various administrative levels with their own systems and services. The existence of numerous and different actors, policies, procedures, data standards and systems results in coordination problems with respect to data analysis, information delivery and resource management.. In this paper we present a novel approach based on interaction models distributed through a peer to peer infrastructure and we show how it can be applied in the context of crisis management to support coalition formation and process coordination in open environments. In particular, a prototype eResponse simulation system – built on a P2P infrastructure – has been developed to execute interaction models describing common coordination tasks in emergency response domain. Preliminary evaluation of the proposed framework demonstrates its capability to support such eResponse tasks.