your workflow sounds like you have one task which is done by different employees each time. However, this task always gets assigned to the same user who then right clicks it and uses the "reassign" function to distribute the tasks throughout the company, is that right?
In this case, I would recommend to implement an additional task which takes place before the actual decision task. Assign this task automatically to the user who distributes tasks and give them only one decision: "assign task". In the Dialog, give one field "Next User" or something like that as a "User from group (Public)". Then, assign the document to the selected user and start the next task. this way, you can put the assignment into a stamp or index data, it appears in the workflow history and it is more comfortable to use.
Hope this helps.
Greetings from Germany,
Simon H. Hellmann
DocuWare System Consultant