Ensure single session per user at a time

Thank you in advance to anyone that can help me solve this one!

I would like to ensure that each user authenticated with restful-auth.
has only a single session at a time. If a user has a session open on
computer A, I want the next place that user logs in (computer B) to
kill/destroy/remove the computer A’s session - for Example. (Same
situation with multiple browsers on a single computer.) This way I can
make sure that each company account has many users with their OWN user
account. (Company has many users - user belongs to company) I don’t
want to force the new log in to be restricted until old session has been
destroyed or expired, I rather just kill the first session and allow the
new login on through.

I am using restful-auth (technoweenie) and active_record_session store.
I have tried using logged_in? call and other conditional statements but
nothing seems to work.

Please let me know if anyone has any ideas, if there are any solutions
already and any help!

Thank you,