Can the band kids come to the band hall during lunch? If you have concerns about food in the band hall, try opening it for lunch just one day a week.
We asked ours and it actually helps the congestion in the cafeteria and now we have "lunch duty" in the band hall. Helps the admin on lunch duty with fewer kids in the cafeteria and gives us our mandatory duty in a space and with kids we know.
I know it's not for everyone but it works for us and our parents and kids tell us we have a family like atmosphere around our program. And I think this has a lot to do with it.