[phenixbb] Exclude Waters from order_solvent=true updates

Hello everyone, I am refining a few structures via a bash script using constrained occupancy refinement by providing a parameter file. I am trying to model the occupancy of a ligand and the water molecules in its vicinity. This works generally well, but as soon as I switch on ordered_solvent=true, these water molecules are also filtered / updated and eventually removed. How can I avoid this ? That is specifically excluding a number of water molecules from being updated ? With best regards, Eike