Hi,
you are looking for this :
There you need to set for one host port 8000 for example and for second host you can let 6556 port. And on your router you need to set port forwarding for port 8000 to one device and port 6556 to second device on local IP addresses.
Don’t forget that IP addreses for your hosts on check_mk server must be same as router’s.
Best regards,
JF