[chimerax-users] Overlay of specific chains

Hi, We have multiple structures of a homo-hexamer (chains A-F). We'd like to overlay limited regions of each chain onto equivalent chains (e.g. residues 200-452 of chain A onto residues 200-452 of chain A). We're having difficulty identifying the correct syntax. Some of our structures align as desired while others are aligned according to the chain combinations that produce the lowest RMSD (e.g. residues 200-452 of chain A align onto residues 200-452 of chain C. Is it possible to restrict which chains align to which? Best wishes, Reza