You would need to set up a campaign and use it's private forum to host the PbP thread. Once the campaign is made you would simply invite your players as normal and they could use the forum to post their replies and the campaign itself could act as a kind of meeting place/chat room if desired. You could also house campaign materials of relevance in the campaign itself for ease of access? Many people host PbP games like this, in fact there is a club (Knights of the Written Word) dedicated to linking PbP and Text gamers together :) Hope that helps.