between Branchburg and Flemington-lunch tomorrow?
Masala Art might fit the bill (ethnic, good food, nothing fancy). I have not been there in a couple of years, but I remember it being pretty good the 3 times I went there in @ 2011-2012, and since there are no Indian restaurants in Fleminton (at least none that I am aware of) it might be a nice change of pace for the colleagues coming from that direction. It's in Branchburg, but a very easy drive from Flemington, straight up Route 202 - - may even be quicker for the Flemingon group to get there than the Branchburg group on Route 22. http://masalaartnj.com/
Masala Art would be a great choice. As I recall, they do a buffet at lunch so that might work well if you're pressed for time.
Since the Branchburg group works near Route 22, you might also consider something in Whitehouse Station. Domo 7 is a pretty decent Japanese spot, especially for sushi. I've had good dinners there but never had lunch.