We will be leaving this saturday for our 5 night Canada cruise and my sister-in-laws (with their two kids) are traveling with us. I understand that tippings are automatic charged to our SS cards. I would like to pay for my in-laws tips for the cruise. Does anyone know if i can have the tips charged to my SS cards while their souvenirs, photos, etc. can be charged to their own SS cards. Thanks in advance for your comments.