Integrated sensing and communication (ISAC) is a key feature of 6G, and is expected to support a variety of vertical application scenarios, where network cooperative ISAC (CoISAC) is essential for further improving ISAC performance. In order to leverage the dense deployment capabilities of 6G networks, this paper proposes an architecture for multi-node network cooperative sensing, which is implemented within a designated sensing function cell (SF). The architecture includes modules of pre-processing, coordinate calculation, and trajectory management. Simulation results demonstrate that the architecture effectively improves positioning accuracy, reduces false alarm probability, and maintains continuous track through handovers in multi-target, multi-false-alarm scenarios. The proposed SF architecture provides a foundational framework for practical multi-node CoISAC systems.