Group of ten looking for Japanese Food 56th Street Area
Depending on the kind of Japanese you're looking for (sushi vs. ramen vs. teppanyaki, etc.) and how much time you have, Gyu-Kaku might be interesting option. There are two around the Hilton but not that close: one on 44th St. between 8th and 9th, one on 3rd Ave between 49th and 50th.
I believe they have both a lunch menu and a happy-hour menu (pretty good deal imo) during Sunday lunch. If I were to eat til I explode I'd say I'd spend $60-70 on food there, but most people will be happy with a $20-25pp portion. Their green tea mille-feuille is from Lady M which I quite like as well.
Do you mean the Hilton on 53rd and 6th Ave?
What's their budget? I assume fairly low given that they are students? How much are they willing to spend per person, for food only (before tax, tip, beer/wine/drinks)?
Is this for a weekday or a weekend? Soon? The holiday season in NYC means that a lot of restaurants are very, very busy.
Ten is a big group, and some places won't take a reservation, though they may be willing to make an exception if you ask. Or at least call ahead that morning.