Hmmm, not sure if you really can block communication with the native VLAN, but only between non-native vlans, but I may be wrong.
I have this new rule set up to block traffic from vlan20 and vlan30
DROP all opt — in ETH01.20 out ETH01.30 0.0.0.0/0 -> 0.0.0.0/0
DROP all opt — in ETH01.30 out ETH01.20 0.0.0.0/0 -> 0.0.0.0/0
Traffic is still able to pass between those two vlans. 😕