Ya, with their mentoring role, this group of others would appear to be keepers of the island and would thus be diametrically opposed to the manipulations of Ben. This keepership role would take the form of guiding souls to the island, imparting knowledge of fate, and likely the oversight of the island's powers. If this separate group does exist, the storyline would likely engender conflict between the two groups of Others. In battling Ben, they may show themselves, however, to be extremely wise and extremely brutal.
Kurt Vonnegut's Slaughterhouse Five involves a character base that is able to see in four dimensions. Time is included in their natural view of a three coodinate world. The Tralfamadorians know the major events of their life, including the manner of their death, and see life in its totality, "the picture on the box," such that all pieces are known at any time.
I believe that this second group of Others hints of the Tralfamadorians. They are not confined to this time and have a serene view of life, their work, and fate.