i think that there would be some of both, but probably not as much of either as you might think.
i think people relate in a variety of ways, confusing and multi-dimensional, especially when there are a lot of cultures interacting.
so how people would relate might depend on what kind of society comes about -- would it be one where there are a lot of smaller groups of people who are mostly insular or where they interact only with similar groups? or lots of small groups who are not insular at all (a la bolo bolo) or would there be big mass societies (similar to the ones that exist today) as pictured in theories like parecon?
this is another of the "huge mouthful" questions, with lots of implicit assumptions that make it very hard to answer (without more detail from the questioner).
