Unfortunately to do this with DocuWare Users and Groups will produce a WHERE clause that will not be able to be parsed by Workflow Manager.
Therefore, create a small table to hold the location and the DocuWare user name.
In the Workflow, create a location variable and a manager variable.
Use the External Data function to assign the user name to the manager variable.
Phil Robson
Senior Director Support Americas
https://www.docuware.com/sites/default/files/forums-images/Location.png