I am trying to generate a unique ID for items in a document library based on values from other fields. I have several lists located at the root of my site, and have created lookup site columns for those lists in order to access them in subsites.
As an example of what I am trying to do, in a subsite I have a library which uses the "Department" site column. In a workflow I am trying to get the selected value of the department field, and set the value of a Doc-ID field (single line of text) to a string with the format "[department]-[ID]".
When the workflow runs I get the following error: "The field 'Deptartment' is not supported in query. The lookup list is in another web."
I'm guessing the problem is not having direct access to the source list? How can I get this working?