Problem creating Gmail filter combining FROM and To fields with OR

I'd like to create a filter that moves any messages based on the From field or the To field.

In the search dialog when I populate 'From' with x OR y and 'To' with z the search created in the filter has an implied 'AND' between the 'From' and 'To' fields:

from:(x OR y) to:z

but I want the filter's search to be:

from:(x OR y) OR to:z

How can I do that?