Multiple sources on category field type - possible? We're trying to setup a category field type to allow the selection of 1 category but from multiple category sources. Is there a simple way to achieve this without writing a custom plugin / fieldtype?

Currently we've set up 4 Category fields to allow a selection from the 4 sources with instructions to only use one of these fields at a time but it feels messy.  Thanks!
You cannot allow selection from multiple category sources in a category field.

I would keep the 4 category fields but set each field to limit to one (1) category selection.

Then, when you add the field to the field layout, make the field required to ensure they select a category for each field.