How to categorize rails fixtures

This is a conceptual question because I want to do this the most effective way. Let's say I have a test I need to run that will return true for some fixtures and false for some others. I want to iterate over the false fixtures and assert a "false" response for them in one test. In another test I want to test over the true fixtures and assert that I get a "true" response from them.

So I would ideally like to categorize a set of fixtures into a true group and a false group and make separate tests for each group. I'm not sure the best way to do this.