Re: Restrict model edits to PMI only
There is a way to find the modifications done by the drafter. Go to Menu->Information->Part-> Modifications...
Select the base version (designer released the part to drafter) and select the criteria After, then click apply.
The listed information will help you to identify the changes done by drafter during his execution. The modified features can be highlighted in the part by clicking the previous / next button.
Hope it'll help you in this case (If you don't want to create a linked part).