Dunwoody / Sandy Springs & Further North
Gu's Bistro on Buford Highway right outside the perimeter would be my #1 recommendation.
Excellent Szechuan style Chinese food that is perfect for large groups as you can order everything family style and just start tasting. Be sure to get the dumplings in red oil, dry fried eggplant and the fried fish with peanuts.
+1 on Gu's i also love the walnut shrimp--fantatsic really. If you call tell Yvonne, shes the owner/chefs daughter what youd like to have and ask fotrone of the booths on the side--they can fit 6 in there easy, if its a bigger group they have large tables in back.Make a res sometimes they get some large groups, esp on weekend--no liquor licens yet, but you can bring in whatever you want to drink