Prevent non-WAN Gateways from becoming the active gateway

[alh]

When default gateway switching/failover is active, is there a way to prevent non-WAN gateways from becoming active? We have 3 WAN gateways and some internal gateways for routing between networks. When all WAN interfaces are down, I don't want one of the internal gateways to become the default gateway. I guess I can solve this by disabling this feature in general and work with a gateway group but just wanting to know if it could be solved otherwise as well.