Today, the "prefer grouping colocated visits" constraint rewards a technician for doing consecutive visits at the exact same location, reducing unnecessary travel. However, in practice, visits near each other (but not at the identical location) would benefit from the same grouping logic.

The request is to extend this constraint with a configurable radius, so that visits within a specified distance of each other are treated as a group and preferably scheduled consecutively. This makes the constraint more useful for real-world datasets where nearby visits are effectively colocated from an operational standpoint.