Convert an STL file into a partially locked Blender file

Job ID: 35501493

Budget: $30 – $250 USD

We have an stl file that we use to 3D print a round, dish-like mold, that is 100mm wide and 50mm deep. We would like to have this file converted into a Blender file to become available for sculpting by a number of freelancers using a recent version of Blender in order to create new molds from this template.
We would like only a few 'regions' of the original stl file to be editable in Blender while the other 'regions' must remain unchanged in relation to the editable 'regions'.
Furthermore, the uneditable 'regions' should be made partially (80-90%) transparent so that they don't impede on the editing, while providing a visual boundary to the part that is being edited.
Can this be achieved in Blender? If so, please indicate your solution together with an indication of cost.
Related categories: 3D Modelling Blender