[Chimera-users] Constrained movements

Dear all, The image below shows 2 chains opened separately from 2 PDB files. I would like to move only the cyan chain. For that, I just have to deactivate the white chain. BUT I would also like to keep fixed a specific atom of the cyan chain, for instance the cyan atom in the red circle. This way this atom serves as a pivot point. I know that I can use "Constrained Move". If I understand well, the "origin" is either 0,0,0 or the center of a model bounding box, not a selected atom. Is it possible to manage this? Many thanks for your help Damien