Comment 2 for bug 1833475

I attempted to do this today and seem to have been successful using netplan.io version 0.105-0ubuntu2~22.04.1.
Running the following configuration, outgoing multicast traffic is being sent from ens256 as intended.

network:
  version: 2
  ethernets:
    ens192:
      addresses:
      - 192.168.212.111/23
      routes:
      - to: default
        via: 192.168.213.254
      nameservers:
        addresses:
        - 192.168.130.40
        - 192.168.130.2
        search: []
    ens224:
      addresses:
      - 192.168.216.111/23
      nameservers:
        addresses: []
        search: []
    ens256:
      addresses:
      - 192.168.218.111/23
      routes:
      - to: 224.0.0.0/4
      nameservers:
        addresses: []
        search: []

I hope this helps.