Geo Eval - Filtering

Thanks to the great documentation and tutorials I've been able to follow along and:
• create an API that queries all records
• use geo distance to calculate distance between two points - returned as integer
• use geo within to calculate if the points are within a certain distance (radius) - returned as boolean
• return the full list of records by distance in ascending order

Where I'm having trouble is in limiting the output response only to the records where the boolean response is true.

Where would be the best place to add that last bit of filtering so the response only includes the items that fall within the preferred radius?