HB session keys - Adding together sessions or buying more for the same key

I own two separate HB single session keys and was considering buying a 3 session key.. but i was wondering if there was some way i could get all these keys added together. I did not see an option for this on buddyauth.com It would be awesome if I could have all my keys in one because sometimes i forget which account is on which key and give myself max session errors. Thanks

edit- i would be buying a 3-session HB key to add to my collection of two single