Hi @robinb
I tested here in my computer your support.
For the solve this, I used just a transformer AttributeManager.
Inside this transformer I configurated like bellow:

As you can check the Workspace template ( attached ), I search for the values from attributees A,B,C - and set the attribute value = Attr_Value.
The result:

Thanks in Advance Workspace_Xls.fmwt
Danilo
Hi @robinb
I tested here in my computer your support.
For the solve this, I used just a transformer AttributeManager.
Inside this transformer I configurated like bellow:

As you can check the Workspace template ( attached ), I search for the values from attributees A,B,C - and set the attribute value = Attr_Value.
The result:

Thanks in Advance Workspace_Xls.fmwt
Danilo
Thanks @danilo_fme - that has got me forward to the next step.