persist.java

@Entity
public class Organization { }
  
@Entity
public class Person { }
  
@Entity
public class OrgPerson {
  @ManyToOne
  @JoinColumn(name = "org_id")
  private Organization organization;
  
  @ManyToOne
  @JoinColumn(name = "person_id")
}

public class SomeService {
  
  public save(String orgId, String personId) {
    // validate orgId and personId exists with Repository.existsById()
    var orgPerson = new OrgPerson(orgId, personId);
    orgPersonRepos.save(orgPerson)
  }
}