Babette, near Piazza Del Popolo, is located on the lovely Via Margutta at number 1d (courtyard at number 3). This pretty restaurant is large and also has a nice courtyard. The food is upscale, the service friendly.  TripAdvisor reviews here.

Checco er Carettiere, located in Trastevere at via Benedetta, 10, is a family-run operation that welcomes groups from two to 50 for dining indoors or al fresco.  Superior antipasti, including Roman-Jewish offerings like deep fried artichokes and stuffed zucchini blossoms, homemade pastas, wonderful fish, and desserts ranging from fruit to dolce (sweets).  The interior walls are covered with photos of Italian politicians, movie stars and singers who have eaten there, while the small courtyard offers a pleasant location in warmer weather. TripAdvisor reviews here.

La Taverna degli Amici is a pretty, ivy-covered restaurant located in a quiet square at Piazza Margana, 37, steps away from the busy Piazza Venezia.  The restaurant, which offers typical fare, can accommodate large groups, and has ample seating both inside and outside.  TripAdvisor reviews here.

Pizzaria Ciro, a casual place located near the Spanish Steps at Via della Mercede, 43, has a large back room that can accommodate groups. The fare is simple but tasty and reasonably priced. TripAdvisor reviews here.

It is prudent to make reservations when your dining party is a large group, even at more casual places, so that you can ensure the restaurant can readily accommodate your party.