I think you need to do sometyhing like this:
2 Global variable. GV_CurrentUser and GV_Role.
Use 2 seperate assign data steps.
1. Assign data - assign the Current User to the variable GV_CurrentUser.
2. In the second assignment step, create an External Data connection as follows:
Connection - Authentication
Table - DWUSER
Field - name
rid in (SELECT rid FROM dwsystem.DWUSERTOROLE WHERE uid in (SELECT uid FROM dwsystem.DWUSER WHERE name = GV_UserName))
Senior Director Support Americas