Hello,
As Alain suggested, you can use local preference for this. Additionally, you can use the 'weight' attribute as well.
Local preference is transitive in nature and is passed on to other peers. A higher local preference is better.
Weight is a Cisco proprietary attribute and is not advertised to any peers. This means that you can use it to influence only the local router you are configuring it on.
If you need examples of how to set this up, please let us know.
Regards,
Aninda
