Put a ticket in and ask them to consolidate your accounts under one B.net account for security reason or whatever.
I tred to get my SC2 licence removed to put it with another one of my B.net account with my main WOW and D3 account on it and they refused but they said they would help me merge them but because I was maxed out on game licences they couldnt do it as they don't split up B.net even if it would be to merge my other B.net account.
So they can merge from what I was told today so give it ago.
P.S. If both B.net accounts only have one game account tell them you have just found out you can have multiple game accounts under one B.net account.