Multiple Categories OR Logic

When searching for a post that has multiple categories assigned to it, it does not find it if only the one category are selected. All categories assigned to the post must be selected.

Let’s say I have a post that is in the categories called, “United States” and “Canada”. If I select “United States” as the filter option in the checkbox fields, the post does not show unless I also select “Canada”. Is there a way to make it search if “United States” OR “Canada” are selected rather than “United States” AND “Canada”?

This is an issue because I am actually hiding the category fields, and setting them via javascript. There is a filter to only show Posts from a single category. The search needs to search that particular category as all wording is telling the user they are in that particular location.