Plutonium

i want to use the friends list to invite and join, is that possible?

I have 2 pcs with 2 plutonium accounts, but only the pc with port forwarding can join games. Anyone have any ideas on how to get around this? I want to have a third computer that can play to, but then one person would always be left out.

For example:
PC1 has a port forward
PC2 hosts a game
PC1 joins game

PC1 hosts game
PC2 cannot join game

If I switch the port forward, then who can join switches too.
I can't tell my router to give 2 computers the same port number.