Ah I understand it now you want to have a kind of shared parameter added to certain model in place elements without using a shared parameter because you won’t want this parameter be added to the elements
I have not so a solution for you.Maybe look into the Orchid package there are great nodes for adding all kind of parameters
https://forum.dynamobim.com/t/orchid-package-released-at-github/22671
I did something with automatically adding parameters to a family file but you want something for a model in place