The Bluffs Bar and Grill is the closest with good food and ample room for 20.
They have their Friday Night fish fry and serve off the menu. The buffet area is generally pretty crowded, but there are plenty of tables in the bar area.
To get to the Bluffs, turn left at the top of Everts hill, go to 35 and turn right. About two miles is the 4 way stop signs. Turn left and your there.
With a party of twenty, I would call ahead no matter where you go.
Many of the Pro’s from Everts can be seen sneeking in the back door of the Bluffs. If you stay late enough Shooter, one of the owners might stop by to say hi.
As an added bonus, ask Dean for the “free drink cards”. One per person please.