"Lock" certain Scenario and Measures combinations?

Summary

Is there a way to "lock" for entry (but still show on forms) certain Scenario and Measures combinations?

Content

Hi,

I need to be able to "lock" for data entry (still show on forms, but with grey "closed" cells) certain combinations of Scenario and Measures, but still allow them to be selected in forms. I tried Valid Intersections approach, but then the problem was that the combinations could not be selected in the form. They still must be able to be selected, just not written back to. Is there any way to do this, perhaps with security or similar?