of you can pick and choose what you want to give. We actually do this with my daughters family and kids as well.
I will also try and buy my wife something beyond what she lists but at least it gives me some ideas of what she is thinking about that she wants for Christmas.
Giftster is a great app because you can be part of groups and if someone buys something is lets everyone know but the person who's list it is that that item is reserved or bought. You can also add a link to the website where the item is found. It'll then show a picture of the item.
Pretty cool actually.