Then i would suggest you step up your game to support it. I understand that *google* won’t allow it. But if you would allow us to target it with a dynamic attribute it wouldn’t be a problem. It is a feature of wordpress (and woocoomerce) to allow multiple categories. One would expect a feed plugin to accommodate.
And just for the record, i tried extracting the wanted category path using a dynamic attribute, but since the “category path” contains *two* category paths (this is a bug in my opinion) it didn’t succeed.