Make sure that all the adults in your party have their own PhotoPass card. This way, when your group slits up, everyone can still get pics taken, and when you are together, make sure that at least two cards are swiped; this redundancy helps to reduce the possibility of your pics getting lost in the PhotoPass system.
And don't be shy about giving PhotoPass cards to the kids, too; just be sure to write down the number from each card in case they get lost. If they do get lost, just get a new one from the next PP photographer you meet.
At the end of the trip, collect all the PhotoPass cards and enter them all into a single account. A PhotoPass account can have hundreds of cards entered into it. But a PhotoPass card can only be entered into ONE account, so if Aunt Ida enters her card into another account, there is no way you can enter it into the group account.
Once all the cards are entered, share the user name and password of the account with everyone else, and let them all view the pics and make copies with borders and graphic enhancements.
When all the enhancements are done, you can order the PhotoPass CD. The CD will contain all of the pics in the account, including the originals and the copies with borders and graphics added. If the whole account doesn't fit on one disk, it will be spanned accross multiple disks with no extra charge.
If any of you have a laptop with you at WDW, you can enter your cards into the account while you are there and view them each night when you get back to your room; this is great, because then you can have any that you don't like re-shot before you go home!
Just remember - a PhotoPass card can only be entered into ONE account! So if Uncle Joe goes back to his room and enters his card into his account, you will not be able to add his card to the group account, and it will not be on the CD that you order from the group account.
And a CD can only have ONE account on it, so you will not be able to get Uncle Joe's account added to your CD. Once a card is entered into an account, it can't be moved to another account, ir can't be removed from the account, it can't be merged into another account. If Uncle Joe enters his card into his own account, then Uncle Joe's pics will not be in the group account, no matter what.
Likewise, once you enter a card into the group account, you won't be able to add the card to any other accounts; so if you add Aunt Ida's card into the group account, then Aunt Ida tries to add the card to her own account later, she will be told that "This card has already been added to an account" and won't be able to add it to her account. This is why you need to share the user name and password of the group account with everybody - then everybody will be able to view the pics and add borders and graphics to them.