In this paper we present an extension of Cooperative Surveillance Multi-Agent System (CS-MAS) architecture to incorporate dynamic coalition formation. A specific coalition formation using fusion skills is shown so that the fusion process is distributed now in two layers: (i) a global layer in the fusion center, which initialize the coalitions and (ii), local layer within coalitions, with the dynamic instantiation of a local fusion agent. There are several types of autonomous agents: surveillancesensor agents, fusion center agent, local fusion agent, interface agents, record agents, planning agents, etc. Autonomous agents differ in their ability to carry out a specific surveillance task. A surveillance-sensor agent controls and manages individual sensors (usually video cameras). It has different capabilities depending on its functional complexity and limitation related to specific sensor nature aspects. In this work we add a new autonomous agent called local fusion agent to the CS-MAS architecture, addressing specific problems of on-line sensor alignment, registration, bias removal and data fusion. The local fusion agent it is dynamically created by the fusion center agent and involves several surveillance-sensor agents working in a coalition. We show how the inclusion of this new dynamic local fusion agent guarantee that, in a video-surveillance system, objects of interest are successfully tracked across the whole area, assuring continuity and seamless transitions.