Indeed.
Timeline-wise, the original HDN was kept apart from MK2, but both Mk2 and Victory are set in the same storyline (though V involves interactions with yet another parallel timeline). PP, the idol game, seems to be in its own stand-alone continuity, while Re; Birth 1 and Re; Birth 2 will presumably be in a shared timeline (but it's too soon to tell if it's meant to be the same timeline/s shown in mk2 and V). Noire, the PS3 stand-in, will be getting her own game on Vita (the one which will be detailed in November's issue of Dengeki PlayStation), but it's not known which timeline that game will be in either.