With a group of 16, a place with a private room is the way to go.
one sixtyblue is another place that has a private room - actually now they have two, one that seats up to 14, another up to 50. They also have their "wine room" which is fun (it's right off the main dining room, glassed in, and you've probably noticed it if you've ever dined there).
If you want to stick to Italian, Vivere, mentioned above, is a good recommendation. Another place to consider (in the same vein - Italian food in the Loop) is
Trattoria No. 10, which also has private rooms.