GUW-- Considering there guys are on "corporate expense accounts", I would think that you could just do lunch at the Four Seasons or Park Hyatt. The good thing at these venues is that they can surely improvise a couple of vegetarian dishes even if they dont have something thats strictly vegetarian on their menus. Your location of Cordoba 950 puts you in decent range of either of these locations, youre looking at a 10-12 minute cab ride at max.

There are tons of eateries near your mentioned address, but I dont think they would be a good choice for your out of town visitors. I think that a large international hotel will have them at be at ease and enjoy their meal in the best possible way.