|Project:||The Hive project|
as it is today, it can't be specified that user Joe has different roles in project X and Y.
Joe might be a moderator for topics in project X, in project Y he might be just a normal reader with only rights to comment and discuss, and he might be totally banned from the secret project Z.
It seems to me we will have to look into the possibilities to fine-tune that.
For starters, this discussion may give a lead: http://drupal.org/node/70555