Dining with party of 7 and gratuity

[julzee]

Ok. So there are a total of 7 of us. 2 seperate reservations. When I make the reservations I was told that was fine to add the whole party together even though we are reserved seperately.

My question-- is everyone charged the 18% gratuity? Because that would be a lot of $$. So there are 5 of us on one reservaition and 2 on the other.
Do they ask who wants the gratuity charge? I guess you see where I am going with this.

Any help would be appreciated. I'm trying to figure it all out!!