Leo, ryan, and matthew regularly interact with one another and share similar values, norms, and expectations. in view of this, which concept most applies to their relationship?

They are a Group.

A group in sociology can be defined as a subset of a culture or society. And it can be said that a culture is the arts, customs, lifestyles, background, and habits that characterize a particular society or nation.

A group can be formed by two or more persons as long as they share common interest, values and goals.

Leo, Ryan and Matthew clearly define a group as they are more than two; they share similar values, norms and expectations.

Leo, Ryan and Matthew are a "group".

Explanation:

A group consists of people who have similar interests and values and expectations and regularly interact with one another towards achieving their common goals.

Leo, Ryan and Matthew can therefore be considered as members of a group.

is there a year set? the question is incomplete

answer; the sons of liberty;