Have BGP track active VRRP in Cisco vPC with DCI

Hi guys, I hope I can explain my situation correctly.

I currently am tasked to connect two DCs to Azure via ExpressRoute.

They currently run the following:

 DCA DCB vrrp master > SW01----SW03 < standby || \ / || vPC link > || X || < vPC link || / \ || vrrp listen > SW02----SW04 < vrrp listen 

• Switches are Cisco Nexus
• SW01 and 02 form a vPC
• SW03 and 04 form a vPC
• DCA is the VRRP master. All routing is done on SW01 and 02 unless there is a failure.
• All four switches will have their own links to the ER and run BGP
• The customer prefers to have all traffic flow over the active side

My question is as follows: If SW01 stops being the VRRP master, fails I'd like to have BGP advertise a more preferred route via DCB. However, I can't think of a way to have SW02 automatically change its metrics to become less preferred when SW01 isn't the VRRP master anymore.

I'm probably missing something really simple or not seeing the obvious, so any help is appreciated!