Better way, it is possible to use all ports on router, each with different radio:
/ip address
add address=192.168.1.11/24 interface=ether1 network=192.168.1.0
add address=192.168.1.12/24 interface=ether1 network=192.168.1.0
add address=192.168.0.1 interface=ether2 network=192.168.0.1
add address=192.168.0.1 interface=ether3 network=192.168.0.1
/ip firewall mangle
add action=mark-connection chain=prerouting dst-address=192.168.1.11 new-connection-mark=port1
add action=mark-connection chain=prerouting dst-address=192.168.1.12 new-connection-mark=port2
add action=mark-routing chain=prerouting connection-mark=port1 new-routing-mark=port1 passthrough=no
add action=mark-routing chain=prerouting connection-mark=port2 new-routing-mark=port2 passthrough=no
/ip firewall nat
add action=dst-nat chain=dstnat dst-address=192.168.1.11 dst-port=80 protocol=tcp to-addresses=192.168.0.2
add action=dst-nat chain=dstnat dst-address=192.168.1.12 dst-port=80 protocol=tcp to-addresses=192.168.0.2
add action=masquerade chain=srcnat out-interface=ether2
add action=masquerade chain=srcnat out-interface=ether3
/ip route
add distance=1 dst-address=192.168.0.0/24 gateway=ether2 routing-mark=port1
add distance=1 dst-address=192.168.0.0/24 gateway=ether3 routing-mark=port2
This config uses only two, because I tested it on three-port RB433AH.