I know this is an older post, but wanted to let you know that this is now possible in version 2.7.9b.
One of the new enhancements is a new config parameter to enable the creation of a unique confirmation number for each group member. Enable this, then you will also get a unique barcode for each member. Put the [BARCODE] and [CONFIRM_NUM] email tags inside of the {GROUP_MEMBER} tag in the ADMIN email to get this info for each member shown in the notification email. The user thanks email will show their unique code and number with the regular existing tag usage.