Private room in downtown Manhattan
Frank's is, indeed, good if you're in a steak mood.
The tribeca grill has a nice room over the restaurant,
Morton's on West Street has a room and the American
Park, down at the Battery, has a room with a
magnificent view of the Harbor that may be too large
for your group. Harry's at Hanover Square has a lot of
rooms, but the food is mediocre.
If your into steaks try Frank's Steakhouse (10 ave.+ 15th St) It's a serious meat ,wine and cigars. It's
kind of like a guys hang-out off the main drag. The food is pretty good, service is good and you never feel like your rushed . but the great thing is that they have a nice size back room. I have been there for
a few functions and they pretty much can put together anything you want.