A group of six are planning to meet for dinner at Washington National airport and I am looking for a restaurant recommendation. The restaurant must be outside the security area and anyplace not at the airport is out of bounds for our purpose. The only restaurant that I have eaten at is Matsutake Sushi, which is fine by me but I am not sure that the rest or the group will go for it. Being closer to the old terminal (A) is desirable because we are meeting a bus outside there at 8 PM. One of the group is a slow walker so Legal Seafood is too far. This is for a Sunday night and we have about two hours for the meal.

I believe you are limited to the following:

Cibo Bistro and Wine Bar - close to A terminal (I only had wine there)
Samuel Adams Brewhouse - in A terminal (not sure if they have food)
Carmella's Kitchen - close to A
T.G.I. Friday's - right across the hall from the Sushi place (the usual TGIF stuff)
Cosi - little further down

I think there might be a Legal Seafood outside security.

Yes, Legal Seafoods is outside security, but it is at the far north end of the airport (C gates) and the OP wants something at the other end.

AAFF (or anyone else) how is the Cibo Bistro and Wine Bar's suitability for a group of six in terms of space and atmosphere. I gather that it is Italian themed food.