Advance Workflow Management will help workflow admin define single workflow with states adding a layer of groups at top of that, access control will be based on groups. This module will create a new tab "Workflow Groups" through which admins can create various roles as workflow groups, assign group role to the user (author/editor/publishers) along with the role that manipulate workflow.
Advance Workflow Management is dependent on workflow module, create your workflow along with the states as you do normally with workflow module. Add workflow groups; for example create two workflow groups through the "Workflow Groups" tab, assign those group role to the different user along with author/editor role. The article written by one group with same workflow will not allow authoring/editing access to the user of other group who are also using same workflow.
Using this module users have restricted read/write access to article, but this is not 100% true because articles that are not in published workflow state but are published in system, will still show up in search or other areas where node_access is used to check access. This is due to the limitation in node_access() function in drupal 6.x that there isn't any hook that can help us do VETO or allow developer to add some more stuff in its processing, either we have to hack that function or there is a view created with this module that will atleast help admins to restrict those kind of nodes through advance workflow management filters on pages and blocks created by views module (I need some help here... :)