Can I disable backups when WAN1 not online?

If my main Internet connection dies, I have a failover Internet connection with a limited data cap as a failover.

Thing is, I’m averaging about 3.3TB of data per month (lots of NAS backups), and I want to disable those backups if the secondary Internet connection is active.

I can check for WAN1’s connectivity in TrueNAS or Home Assistant, but I still need some way to tell TrueNAS to temporarily disable remote backup tasks while WAN2 is the active connection.

How would I temporarily disable remote backup tasks?