In recent works, we introduced Swarm-CG, 7,9 a versatile optimization software that is able to integrate bottom-up and top-down references in a multi-objective and multi-directional optimization framework for coarse-grained models. Building upon Swarm-CG's capabilities, we propose a novel strategy for optimizing three-site water models by incorporating experimental data on the microscopic structure of water, particularly the radial distribution functions (RDF) of its atoms. Specifically, we utilize the Oxygen-Oxygen RDF (g OO ),