Hub Transport rules for multiple custom headers problem?

Hello,

What I'm trying to do is add custom headers on messages sent to specific email in the domain, with a Hub transport rule. It works, but if the mail is sent to multiple recipients in the domain, it should end up with multiple headers as well, but it only keeps the header added on the lowest priority rule.

The rule is as follows : 

Apply the rule to messages
Sent to 'blahblah@blah.com'
Set 'X-customheadername1' with 'customvalue1'
and Blind carbon copy (Bcc) the message to 'user1@blah.com'

Using the "Sent to" event makes the rule run even if the message was Bcc'ed to that address.

Further down the Hub Transport Rule list, is something like this :

Apply the rule to messages
Sent to 'blahblah2@blah.com'
Set 'X-customheadername2' with 'customvalue2'
and Blind carbon copy (Bcc) the message to 'user2@blah.com'

If the same message is directed to both addresses, e.g. blahblah1@blah.com and blahblah2@blah.com, it only gets Bcc'ed to user2, and only the X-customheadername2 exists.

Is there any way around this?

What I'm ultimately trying to do, is Bcc messages with a custom header to specific addresses, which then by an outlook rule would get delivered to a specific folder in the user's Inbox.

Would setting Set-TransportConfig –HeaderPromotionModeSetting MayCreate as described here help? http://blogs.technet.com/b/stuartp/archive/2009/12/08/new-feature-in-exchange-server-2007-sp2-headerpromotionmodesettings.aspx

Regards