setting up a home network can be tricky, but the UPnP settings should help (in LW's Advanced Firewall options).

If not, force each machine to have a unique static IP and port.

Then find out how to set the router to "forward" the port to the proper static IP.

Once done, each machine will be able to "accept incoming connections" (use that search term to find the details on this forum), you can set thre port in the manual section of LW's options, and your speeds should improve.

I know: easier said than done