enable / disable filter rule from command line

[fratotec]

I have Opnsense with 2 Internet providers and a dual IPSec routed VPN to a Azure Gateway. Both VPNs are working, but I have a LAN rule which directs LAN connections to the Azure net via one of the 2 gateways.
What I try to accomplish is to switch the rule to the secondary gateway when the primary fails.
Perhaps triggerd by "leftup/down" scripts from ipsec.conf ...

Ideas how to do this ?