Ability to Close Comments on Idea After Being Promoted to User Story/Feature Merged

We are encountering a business problem between our idea intake management, and promoting to a user story / feature where as comments made on the intake idea potentially impact an already promoted user story. This can take the form of additional change requests, scope creep, or relative important information commented on an idea, which do not populate or link to the user story(s) level or beyond.

A potential solve we want to explore is closing intake comments to the idea once it has been promoted, and allowing the submitter only to reference the original intake idea via new thread.