NONE of the given workarounds here (macros, styles etc.) solve the problem mentioned initally. What you need for a proper review with multiple roundtrips are FIXED and VISIBLE comment numbers which do not change even if you add more comments.
In the "real world", complex answers to complex comments are often given in external documents, excel sheets, emails, handwritten or on Skype meetings: "Let's look at comment number 123. Everybody on the same page?"
This was nicely implemented in old Word, when comments started with something like "FK123", in print AND screen version - with "FK" as the author's initials and "123" as a fixed/constant/static number, even if you delete older or insert preceding comments.
How hard can it be?!