Highlight matching text in unrelated dimensions

[data_RN]

Hello All, 

Hopefullly I am just missing something obvious 😣

I have two unrelated dimensions that I want to compare and highlight based on matching text.  If a result in column A matches a result in column B, I would like to highlight it in the table. 

I have tried this:

=If(If(PType = 'Small', PName) <> Item, yellow())

but this only works if the results show on the same row using.

I would like it to look like this: 

If(PType = 'Small', PName)	Item
Oak	-
Ash	-
Alder	-
Birch	-
-	Oak
-	Alder
-	Forest
-	Linsen
-	Cotton

Any suggestions would be greatly appreciated 😊

TIA!