this failover group is added na rin sa firewall rules, tama? otherwise it wont work.
the problem kasi with your question is pf doesn't have a trigger to do certain firewall rules kung mawala primary line.
it still assumes the same rules with the secondary (Tier 2) when Tier 1 fails. As if the developers presumed the same speed will be used with T2. if you think about it, it makes sense in a way that bakit lagyan ng fail-safe feature kung hindi rin naman kakayanin ng back-up(T2), otherwise same speed na lang sa T2 ang kuni para sa T1 kung ganun, cheaper pa, di ba? baka inisip nila pang corporate level siguro. To compensate for the lesser speed, i suggest na create ka na lang ng strict firewall rules na specific for your DSL to load and reboot when your Fibr fails. pero very academic yan 1M down/ 0.5M up won't cut it for surfing with 5Mbps down speed, theoretically sa iniisip mo max users mo lang will be five.