Reference "ITEM" and "Source Subinventory" fields from the UI in Valueset

Summary:

Reference "ITEM" and "Source Subinventory" fields from the UI in Valueset

Content (please ensure you mask any confidential information):

We are trying to define a DFF for Requisition, which will have the query-based ValueSet. In the query's where-clause, we want to reference the fields from the UI to limit the values only for the entered Item and Subinventory.

We have previously used the UI page variable as :{SEGMENT.TASK_ID} in procurement to reference the Task from the POET fields. Looking for similar variable for above two fields from the requisition page

Version (include the version you are using, if applicable):