According to rule #6, for the construction to be an exception "the context must explain or point out plainly the person to whom the two nouns relate." I believe there is a possibility that the context provides the exception. However, given the context, even if the two datives here are not identical, it would seem that they are overlapping concepts.
Heb 12:22 But ye are come unto mount Sion, and unto the city of the living God, the heavenly Jerusalem, and to an innumerable company of angels,
Heb 12:23 To the general assembly and church of the firstborn, which are written in heaven, and to God the Judge of all, and to the spirits of just men made perfect,
Heb 12:24 And to Jesus the mediator of the new covenant, and to the blood of sprinkling, that speaketh better things than that of Abel.
The context is the three verses, which together provide a list of datives indicating all the things to which "ye are come." Given this, it would be impossible for "ye" to "come" to two ontologically distinct entities that have their own programs and destinies.
1. mount Sion
2. the city of the living God
3. the heavenly Jerusalem
4. an innumerable company of angels
5. the general assembly
6. the church of the firstborn
7. God the judge of all
8. the spirits of just men made perfect
9. Jesus the mediator of the new covenant
10. the blood of sprinkling
1-3 = the geographical location in heaven
4 = the non-human cohabitants
5-6 = the names of this union of saints
7 = God, the orchestrator
8 = Old Covenant saints
9 = Jesus, the mediator of the New Covenant
10 = the means of the mediation
The word for "general assembly" (πανήγυρις) is essentially a
hapax legomenon (a word found only once), coming from
pan ("all") and
agora ("gathering"), referring to a festive unity. A church (εκκλησια) is also an "assembly" of "called out" ones.
Even if the grammatical construction does indicate that the "general assembly" and "church" are stating the same thing (such that one could serve as an appositive to the other), they express similar concepts and are not ontologically distinct. There is simply nothing in the context to separate these two datives into two ontologically distinct entities.
If what you suggest is true, quite a few translations get it wrong:
From
http://bible.cc/hebrews/12-23.htm
New Living Translation (©2007)
You have come
to the assembly of God's firstborn children, whose names are written in heaven. You have come to God himself, who is the judge over all things. You have come to the spirits of the righteous ones in heaven who have now been made perfect.
English Standard Version (©2001)
and
to the assembly of the firstborn who are enrolled in heaven, and to God, the judge of all, and to the spirits of the righteous made perfect,
International Standard Version (©2008)
to the assembly of the firstborn who are enrolled in heaven, to a judge who is the God of all, to the spirits of righteous people who have been made perfect,
GOD'S WORD® Translation (©1995)
and
to the assembly of God's firstborn children (whose names are written in heaven). You have come to a judge (the God of all people) and to the spirits of people who have God's approval and have gained eternal life.
among others.
