Here, have a pair of nexuses (nexi?)...
As for having a trio of protagonists, each with their own take on a given mission (
reference)... the first Killzone did this; hopefully Rockstar won't make Guerrilla's mistake of not leveraging that into a co-op play mode. And being able to jump among the three in a given mission is something we'll also see implemented in Insominiac's upcoming 3PS
Fuse (which looks quite fun in its own right).