By ordering of rank Nietzsche probably refers to a differentiation between base and noble types of man.
Nietzsche rejects other-regarding moralities steeped in pity and compassion, because this ultimately constitutes a life-denying mode of existence. This statement seems to be a clarification of his preferred replacement.
An individualistic morality could be read as ethical egoism, a morality that is only concerned with the well-being of the agent itself. This isn't sufficient for Nietzsche's purposes. Nietzsche is concerned with issues of cultural decadence, not just individual decadents. He is concerned with life-affirming, great individuals, not merely for their own sake, but for the rejuvenation and flourishing of culture. Thus the prophet Zarathustra is not merely concerned with himself - his boundless, overflowing energy necessitates him coming with a message for those who are worthy of listening. Note that Zarathustra very early on gives up on the prospect of elevating all of humanity - he is fine with the slavish herd staying slavish.
A light hath dawned upon me. Not to the people is Zarathustra to speak, but to companions! Zarathustra shall not be the herd's herdsman and hound! (Thus Spake Zarathustra, Prologue, Section 9)
His intent is to elevate those who can be elevated. He is fine with the herd staying the herd - he wishes to seduce people away from the herd, and expects that the herd hates him. But there rightfully is concern for humanity (here understood more restrictively as the idea of humanity, rather than all humans, undiscriminatingly) that stems from overflowing love - and Zarathustra as the herald of future morality reflects this to some extent.
It is also instructive to consider the targets of Nietzsche's philosophical critique, and what his motivations are. One of Nietzsche's major criticisms of Christian morality is that it is all-leveling - all are equally guilty, all are equally damned before God. If all are equal, there can be no mortal hierarchy. The strong are prevented by the ressentiment (resentment) embodied in the pervading slave morality from expressing their strength, and asserting their nobility.
His philosophy, in sum, has a communitarian aspect - not because all members of the community are valuable, but because the idea of rank and nobility is essential to him, and hierarchy is necessarily accompanied by community.