Yes. You will meet at the entrance to World Showplace (the former Millennium Village). The people in your group will be assigned specific table(s). (The tables are rounds set I think for ten.) If I recall, the time I went there were about 120 guests.
There are four buffet areas set up, each themed to a different country and these can vary. Standard non-alcoholic beverages are brought to the tables by the wait staff. I don't recall (since I don't do wine), but I think bottles of vine were available for purchase.
There will be a couple of "streetmosphere" people wandering around with microphones asking questions and keeping the groups active. Also here will be games and quizzes for the kids. There will be character visits and photo opportunities.
About 1/2 hour before IllumiNations, the entire group will be escorted to one of the water-level areas below England or France for a Dessert Buffet and viewing of IllumiNations.
I intend to do this again. Because I live in the WDW area and have lots of friends visiting, I can get myself attached as one of the 20% not staying on property but being part of a Grand Gathering.