One might think that morality is a matter of promoting the good of one's society, understood as an entity in its own right. (I think that Peter may believe something along these lines.) An immediate problem is that we might reasonably doubt whether there really exists any such entity, or whether we can sensibly talk of it having a 'good', or welfare interests. But even if we can ascribe a societal telos -- longevity and power, say -- there's the more fundamental problem that the society might be objectively bad, and so not worth helping at all.
Imagine a dystopia of ruthless efficiency, where individuals are brainwashed from birth and tightly controlled by faceless institutions. Members eat dull, nutritious food; work productively on uninspired projects that increase the power of society's institutions (though never, of course, its private citizens); and reproduce in sufficient numbers to further support this 'purpose'. The society is little more than a virus, propagating itself to no higher end; still, we may suppose that this miserable situation is perfectly sustainable. So there seem no formal grounds to deny that the continued exploitation of the people could in fact be good for the State ("society").
Suppose, by some fluke, you manage to overcome your brainwashing. Are you morally obligated to continue to serve this society? On the contrary, it seems far more plausible that you're obligated to destroy the miserable institutions and start a whole new society in its place -- one that will be better for its inhabitants.
I conclude, then, that people are not universally obliged to serve "their society", i.e. the institutional order they actually happen to find themselves in. At most, we are obligated to serve our collective, which is simply us - a plurality of persons - and not some impersonal entity that exists over and above us. (Perhaps this is all that was meant by 'society' all along?) But even then, it wouldn't do for us to exploit some other group of innocent people, even if it would be to our society's advantage. So we need to expand the collective to all beings with moral status. We might call this the 'universal society', but it's no longer clear that the label is doing any real work.