Thank you bcp for all your answers.
We have tried several solutions but none of them is suitable for all our constraints (no assembly dimension, no right to assemble 2 components with the same function ... )
We have chosen to make two assemblies, one for the PMH and one for the PMB.
This gives us more work in case of modification but it is the only compromise found between the cartoonists and the managers.
Good luck to you.