The answer is not easily. I also believe that Apple has a strict limit imposed on how many "groups" a year that can be made. My work around for this is to use iTunes gift cards. This will make purchases on your account from them an not the credit card on file. You will still be nagged about the credit card CCV number of your an adult though. Apple had to do something to keep this from being abused by pirates after all.
If your concerned about the email receipts, they will always be sent to the group "head" regardless if your purchase comes from gift cards or not. If that is a concern, for instance you wish to read "Fifty Shades of Grey" without ridicule, you either need to be the head of the group, not in a group, or have someone heading your group that doesn't care.
HTH