Bulk edit with limitations for agents

Currently, any agent can bulk edit tickets for any field, even if that field is blocked for agents, this impacts on several fields that we use as metrics, such as CSAT fields, the agent can change his CSAT score through of bulk edit, Zendesk should let us limit some fields for bulk editing for agents.
Or create a trigger condition that catches the update of any custom field, to be able to monitor whether the fields are being changed manually by the agents.