John Deerfield , Sep 22, 2009; 12:47 p.m.
Unless the place is better lit than any I have been in you are OoL (Out of Luck). f/2.8 is too wide for a group of four or five people. You will need at least f/4- and even that wouldn't be optimal. Shooting f/4 inside is probably going to give you a very slow shutter, again not optimal for people, they have a nasty habit of breathing. So it's time to pick your poison.... f/2.8 and know some subjects will be OoF, pick an insane ISO to use a smaller aperture and faster shutter but know that your image will have some noise, or bite the bullet and bounce a flash off a wall or ceiling.