A family of Microsoft word processing software products for creating web, email, and print documents.
Word does not support blocking of specific individuals from viewing comments within a single document.
As a workaround, you can make a copy of the document with the comments, and delete from the copy any comments that you don't want to share with everyone. Then you can use one of several methods to limit the ability to open the commented document to one group of users, while allowing access to the uncommented document to the other group.
For the commented document, you could apply a password (which also causes the document to be encrypted) that's required in order to open the document; then supply the password to the proper group.
You could store the commented document in a protected folder in SharePoint to which permissions are granted only to the proper group. The uncommented document can be stored in an unprotected folder, or a folder that's protected with a different set of permissions.