Adjust bbpress

Hello, I need bbpress plugin to be adjusted. We need: A forum for two parties, one the buyer and one the seller. -Sellers should only be able to post and edit their post and see no other posts from other sellers. -Buyers should be able to see all posts but and reply to them but not be able to edit or post one themselves. This also has to work together with payment membership pro wordpress plugin: [login to view URL] all users of the forum should have a membership to get into the forum. This is how it all should work: A seller places a project like on freelancer via the forum as a post. The seller can see his own post only when logged in and see no other posts from other sellers. He has to be able to adjust the post at any time. The seller has to see all the replies to his post(s) and has to be able to reply back. The buyers should register in the forum too to see the posts the sellers have placed. The buyers should not be able to edit or place posts themselves only reply to them. Shortly: it works kind of like freelancer. Someone who places the project and someone who reacts to it.