Creating 2 mailboxes on Exchange

Hello,
WE have 2 exchange server on one organization i want to create 2 mailboxes for one person with one of server so if user will go to another site he will access it locally.

Here is what i do.(Take note that only one user own this 2 mailbox)

1. i create mailboxone mailboxes for siteA
2. i create mailboxtwo mailboxes for siteB
3. I set to forward all email message of mailboxone to SiteB
4. I set to forward all email message of mailboxtwo to SiteA
5. Then I hide only mailboxtwo from the address book.

This is currently working the only problem is that onces i hide the mailboxtwo it prompt me with the error message “Couldn’t find the recipeints name” when im creating profile in MS outlook.

Do you have any more to suggestthanks..