Make Supplier field mandatory with conditions in Redwood Enter a Requisition Line

I am trying to Customize the Enter a Requisition Line for both option: By selecting an Item and without an item. The conditions I am adding is that if the option "No, enter details" is selected, then the Supplier and Supplier item field should be made mandatory. This I was able to achieve by adding Business Rules Like shown in the attached screenshot-1.

I want to add another condition to it where in I want to make the Supplier and Supplier Item field blank when the Line type is not equal to Goods. I am unable to put values in the Business Rules for a variable. Has anyone tried this? Is it not supported yet?