A three quarter circle of people with a locked off camera occupying the fourth quarter will enable you to get everyone in. Then, even a couple of el cheapo omnidirectional mics hanging down from the ceiling (just out of frame) towards either side of the circle (left and right of the camera) would be better than relying on the built-in camera mics.
But if you can’t even get hold of el cheapo mics, try to record in as small a room as you can – this will help to bounce the audio toward the camera mics.
