For what kind of game? Dove, ducks, geese? We go to http://www.krro.net/
for dove hunts but they also can do geese/ducks (think Ranger Creek uses their facilities for lodge if a large group). 3.5 hours from Dallas near Albany/Haskell. They have access to tens of thousands of acres for all game though and two lodges that sleep 30 to 40 each and been doing this a long time so it is a first class operation. I have heard some other places out there that are popular do not offer a first class operations as they might make you believe. This place caters to the client.
Closer to Dallas you have Rough Creek Lodge which is probably the nicest in Texas. (quail/fishing cha ching but no migratory even if they say dove it stinks there!)
There are plenty of nice ones but don't know if they can accomodate that large of a group but depends on the game.