/interface bridge add name=vm-bridge
/metarouter
add name=mr0
add name=mr1
/metarouter interface
add virtual-machine=mr0 type=static static-interface=ether1
add virtual-machine=mr0 type=dynamic dynamic-bridge=vm-bridge
add virtual-machine=mr1 type=static static-interface=ether4
add virtual-machine=mr1 type=dynamic dynamic-bridge=vm-bridge