This paper proposes a real-time decentralized control algorithm in multi-area active distribution network relying only on dispersed Battery Energy Storage Systems (BESSs). In particular, we propose a zonal control strategy targeting voltage support and line congestion management. The proposed zonal control relies on an accurate dynamic model of BESSs capable to account for their DC active power limits. The communication among different areas is defined using the concept of multi-agents. The effectiveness of the proposed zonal control is assessed and compared to the equivalent centralized control problem using a test case composed by the IEEE 13 nodes distribution test feeders suitably adapted to include stochastic generation and BESSs.