Proofing - Locking stages

Hi! Something that would be beneficial in my company would be an added version to locking proofs.

Here is the scenario for me specifically:

I send out a proof to a huge list of people (Stage 1)

It automatically locks when the next stage starts.

Stage 2 are the designers who review comments from Stage 1.

I need Stage 2 to also be locked at the start of the stage (2).

Stage 1 still needs to be able to review the proof at all times.

Stage 2 doesn't need to make comments/approve anything. They want it locked so the designers don't accidentally change or delete anything.

Having different locking variations would be really helpful in this situation.