Share editing privileges for locked areas in Google sheets

Hello,

How can I share editing privileges for locked ranges of cells in Google sheets?

I've got a Google Drive spreadsheet in which I have locked the first three columns on the left and all of the heading rows. The remainder of the sheet is unlocked.

I've shared a general "can edit" link with a number of people so they can enter data in the unlocked areas of the sheet. As I expected, those who use this link cannot edit the locked areas.

Now I've got someone with whom I want to share editing privileges for the entire sheet, including the locked areas.

Is there any way to do that?

Thanks