Society's goals according to aristotle

Aristotle called happiness "the highest good" and said an enlightened society would be ordered with the goal of helping it's citizens become happy.

but this immediately bring to mind: what happens if the happiness of a societies citizens comes at the cost of other people's/society's happiness.

perhaps the only way for this to be true is if the "enlightened society" in question was global phenomenon and "it's citizens" meant every human being (or even animal?)

happiness may be the highest good, but is it truel 'good' if it comes at the cost of others' happiness?