We're looking for an excellent authentic spanish or mexican restaurant in the Boston area to celebrate my father-in-law's 75th birthday. South Shore would be even better. It needs to have a nice atmosphere, great authentic food (to those who have tasted the real thing), not be too exorbitant in price and ideally able to handle a sizeable group. I know it's a lot to ask, and it might be tough to get all our wishes fulfilled, but any suggestions are greatly appreciated. Thanks so much in advance!