Many people now think of kinship in concepts of people with or without legal or blood ties who feel they belong together and wish to define themselves as a family. Such groups are called:

"Families of affinity" is the correct answer.

Explanation:

Sociological affinity refers to "spiritual parentage", curiosity, as well as other behavioral common interests. This is distinguished by elevated degrees of friendship through collaboration, also recognized as affinity collectives or groups, typically in similar organizations. Individuals who believe they connect collectively, both with as well as without legitimate as well as blood relations, and also who identify oneself as kin.

So that the above would be the appropriate answer.