I emailed GG today asking about the procedure for adding liquor to a grocery order. Here is their response:
If the order has not been placed/paid for yet, you may do this in the "Special Instructions" box in the "Delivery Information" section at check-out. If the order has already been placed, simply reply to this e-mail with your alcohol requests being sure to include: brand preferred (if available), price range, size, quantity and any other specification.
We also ask that you provide a second preference in the event your first choice is not available. Once the request is received, a representative will be in contact to confirm the order and to obtain payment information as this is not kept on file for security purposes. We deliver alcohol as a courtesy, a grocery order must be placed and there is a $40 minimum. Absolut Vodka ranges from $22.99-$42.99, depending on the size. Absolut Citron and Absolut Mandarin are also available. If you have any further questions or concerns, please do not hesitate to contact us.