As was stated, transfers are out, but you can always issue a cert for x days from each account.

Also, some reports have claimed success at combining accounts a la mutual fund in non-spouse same address situations. Success rate has not been 100%, but some claim they've been successful. It may depend upon the rep you get when you call.

And there is a page for "combining accounts" from the Member Services tab once you've logged into the HHonors website. I have no idea of the consequences of using this page, but it might provide another opportunity.