Well, yeah. All we know about mystery group is that they're refined; they're not the savage wolves, even if they do end up matching them for cruelty. They're a 'mafia' of sorts after hearing their authority over the mini-group Daryl worked alongside. We weren't shown the leader's face, which suggests he's being kept back for a later reveal (it couldn't be 'you know who from the comics' surely?!) and another skirmish at Alexandria doesn't seem too far away in the grand scheme of things. It'll be interesting to learn more about the new group. We inevitably will see more of them, hopefully before the mid-season, and they can be expected to provide stern opposition in the second half of Season 6.