Small teams of mobile robots provide nowadays the ability to assist wireless sensor networks in many threatening scenarios that unexpectedly arise during their operational lifetime. The perceived risk or vulnerability that the network is exposed to triggers an immediate, corporate action from the robotic agents (actuators). We focus on a sort of robots which are able to carry static sensors and deploy them all over the field. Our goal is to improve an existing riskdriven collaboration framework between stationary sensors and mobile carrier robots by incorporating an online clustering architecture to better visualize the spatial structure of the sensing nodes in the risk feature space. In this way, we can promptly react to the perceived irregularities in the system's functioning. The proposed framework will be empirically validated in the context of a territorial security application.