Request to add a option (similar to -f killswitch) that works with a bridged (Br0) interface

[undercoverbeatles]

I'm using openpyn on a dedicated old pc configured as a Debian router. The Lan and WiFi ports are bridged as interface Br0. When using openpyn, the -f switch works well as a killswitch on the router interface itself but could we also add a iptables killswitch option for Br0 such that in the event the VPN did drop, Br0 would drop traffic and not leak. Thanks!