Track CARP peer and execute script on up/down status

[ACiD GRiM]

I have two pfsense vm's that I'd like to use as failover for my single DHCP IP on WAN from my ISP. I've got CARP setup for connectivity for LAN hosts, but if one router goes down in my current configuration, the internet is lost.

Is there a way I can detect CARP peer status either via a custom modification via CLI, or in the webui, and execute a script to set the WAN up or down based on the peer status?
This way I can set the WAN if on both routers to the same MAC, and when the primary fails, the secondary will enable the WAN and request an IP from my ISP without having to reboot the router.