Exchange 2010 / 2013 - Ambiguous URLs, Static MAPI Ports and a Loadbalancer

Hi Everyone, 

in a scenario like this: 

From this article. 

Where Exchange 2013 is already in place together with Exchange 2010, and shares the same namespaces, but the MAPI ports on Exchange 2010 are fixed to ... Port1 for MAPI, Port2 for addressbook..etc. 

Would it be possible to address the Ambiguous URL issue with a Rule on the Loadbalancer which sends the Outlook Clients back to Exchange 2010 if they are going to speak MAPI over the defined ports ?  In our tests this worked like a charm. 

thanks in advance, 

Rob