Might I suggest a much simpler solution? Use 2 switches and dedicate 1 to each MikroTik. Make sure your WAN and LAN links for each MikroTik go to a separate VLAN (call them VLAN-WAN and VLAN-LAN). In the end VLAN-WAN will have 3 ports and VLAN-LAN will have at least 2 (and probably the rest of your...