If you don't get a private room, I think you will wait a long time for an area large enough to seat 30 people.

Besides you couldn't talk to everyone. You might consider breaking it down into three reservations of 10 people each to allow the restaurant to better seat your group.

We had this issue years ago when my sister insisted all 15 of our family sit at the same table and then got ticked off that parties of 2 and 4 went in as we waited for space to seat 15 together became available.