How to associate all the m2m apps as belonging to a certain organization?

org-a-m1-app, m1-client-id, m1-client-secret
org-a-m2-app, m2-client-id, m2-client-secret
org-b-m3-app, m3-client-id, m3-client-secret
org-b-m4-app, m4-client-id, m4-client-secret

Can I use client id + secret credentials for an app to uniquely identify a machine?
Can I use client id + secret credentials from m1 and access the service from m2?
How to associate all the above machines as belonging to a certain organization?