Collecting login data on the network

[Berduchwal]

I have a local network at work with all PC ruining Ubuntu 14.04 desktop.
All PC have the same usernames and passwords. Not synchronised simply set up this way.
I need to set up a system which monitors who and when logs in to them. Logins are only local.
I already learned that I can see this information in: /var/log/auth.log
I would this information to be collected from the PC when they are on.
Perhaps by some kind of Cron scrip and placed in a text file on one of the PC.

I have some little experience in writing scripts and I would like to do it alone but I would appreciate some guidance on the best way of doing this.

[SeijiSensei]

You can tell the logging daemon, rsyslog, to write all its output to a remote server (http://www.thegeekstuff.com/2012/01/rsyslog-remote-logging/). Set up each client machine to log to a common server.

A better approach in the long run is to have authentication handled by a common server with LDAP or NIS.

[Berduchwal]

Thank you.