Can sharepoint designer 2007 ment this workflow:

One person (A) posts a discussion to another person (B),who in turns can post to another person (C) such as newsgroups but without without the ability to modify the discussion posted by (A),and this cycle can continue till all the discussions are archived.and once posted the only person who can see the discussion is the one sent to him.I want to find a way to set read permission to the already posted discussions.

Thanks in advance