CRM 2011 Multiple Email Router installed on different machines

Hi All,

I have two SQL Servers where Email Routers are installed,

SQL Server 1 - Email Router 1

SQL Server 2 - Email Router 2

When ever a email is created and status is Pending Send, which email router will pick up this email? Is there any algorithm defined to find out which Router will pick up email for this type of Email Router installation.

Regards,
Saad