How to create a single calibration for all cameras?

Thanks, @otrhan, that works for a new project, but not for a project that has already been aligned. So I can just do it that way. My purpose is to prepare fixed prior calibrations for future projects. I hope to generate XMP files for new images, that have the camera and lens calibrations as ‘locked’ settings, so that only poises and points will be estimated. Is that feasible?