I know Wildfire in Lincolnshire and Glenview both have private rooms that could accommodate your size group; if you're not opposed to a LEYE, they have a real nice dinner package that's about $30/pp from apps to dessert.
On a much more casual note, there's always Hackneys, the Wheeling location is a kind of dump but the burgers are good. Bob Chinn's has space as well. I live in NOrthbrook and these are both real close to me.
Demetri's on Lake Cook across from Home Depot has a reasonable group setup as well.