No it is not written TO a hereafter group. It is written TO the seven churches ABOUT the hereafter, which was not necessarily centuries away. Hereafter can mean a year or so away.
What says it was written TO a hereafter group? It benefist us, but WAS NOT WRITTEN TO US.
Like GALATIANS. It's pure word of God, but not written TO us, but FOR us.
We read John wrote TO the seven churches. But never read TO a HEREAFTER GROUP.
Revelation 1:4 KJV John to the seven churches which are in Asia: Grace be unto you, and peace, from him which is, and which was, and which is to come; and from the seven Spirits which are before his throne;
Revelation 1:11 KJV Saying, I am Alpha and Omega, the first and the last: and, What thou seest,
write in a book, and send it unto the seven churches which are in Asia; unto Ephesus, and unto Smyrna, and unto Pergamos, and unto Thyatira, and unto Sardis, and unto Philadelphia, and unto Laodicea.
To continue with what HE TOLD JOHN TO WRITE TO THE 7 CHURCHS ABOUT, Jesus saqid:
Revelation 1:19 KJV Write the things which thou hast seen, and the things which are, and the things which shall be hereafter;
He never informed John that the direct audience of the book was to a hereafter group of people, but to the seven churches ABOUT the hereafter issues as well as things in past (THINGS WHICH THOU HAST SEEN) and present (THINGS WHICH ARE).
HEREAFTER is a term used to describe the THINGS he would write about, not a group he would write to. Any English scholar or teacher will confirm that.
never did Jesus CHANGE THE AUDIENCE from the seven churches to anyone else. Especially not a particular group he called HEREAFTER PEOPLE.