Of Hillstone's many quirks—no hats in the dining room, no parties larger than four—the free hot towels are the most endearing. As the menu notes, they're available upon request. Shout "Hillstone" in a crowded room, and at least five people will ask what you’re doing for lunch. Such is the effect of this upscale chain, which, depending on the state you’re in, also goes by names like Houston’s, Gulfstream, and R+D Kitchen. Founded in Nashville in 1977, Hillstone Restaurant Group has a single location in NYC, a few blocks from Madison Square Park. It’s a dark, expansive room with a lively bar are