I am familiar with the doctrine of the sealing power, which "refers to the marriage of a husband and wife and to the joining together of children and parents in relationships that are to endure forever." (Encyclopedia of Mormonism)
It's obvious that family relationships will endure beyond the grave, however what about deep friendships? There are those who might even consider certain friendships to be as strong as family ties. What is the official position of the Church regarding whether these also "are to endure forever"?
The larger meta-question is "what is the nature of the celestial society?" What kind of associations will there be among those who aren't sealed to each other as opposed to those who are? If there isn't a statement addressing this directly, what can be reasonably inferred from existing statements and doctrine?