In the context of multi-robot exploring, we work on the particular problem of maintaining communication links between an explorer robots and a base station using autonomous robot routers. In this paper, we propose and describe a kind of exploring application which considers a variable amount of robots over time. This problem opens various research challenges. Afterwards, we focus on the problem of maintaining a single chain of router robots between an explorer and the base station. We propose an simple algorithm for driving router robots. The algorithm generates reactions using a heuristic that considers network changes perceived by RSSI measures. Actions performed by router robots depend on achieving goals consisting in algebraic relationships between current and past RSSI values. Simulation results show effectiveness of the proposal allowing to drive router robots to good positions, in a free-of-obstacles environment, considering the proposed heuristic and the adopted simulation model.