Matchy-ness
This endearing term is used to describe the act of person(s) or thing(s) resembling one another. Two objects (people, for example) are able to bear matchy-ness in several facets of their accord however, the most appropriate manifestation of said matchy-ness to the rest of the world is through physical attributes.
...yeah those tie-dye shirts they were wearing really demonstrate how like-minded and connected they are. Such a great archetype of matchy-ness.