How to get more people playing in same house?

[Guesty07]

Hi, I recently began playing project 99 less than 2 weeks ago. My uncle (who got me into the game in '00), started yesterday. Today his youngest son tried to play but had problems with IP address. I gather this is due to boxing issues. How is my uncle and his family (youngest son for certain, eldest son and wife possibly) able to get around this? Thank you for any help.