Business Security

Hi,

I hope that, somebody can help me with this issue. I just have entered to a new company as a Basis support but I found out that the SAP R/3 System users of this company, use to share they users and password in order to access the system, and now I have the request to prohibit this. The question here is how can I deny user access to the system from several terminal at the same time?

I hope that you can help me with this issue, cause this could cause a lots of trouble in the long way to the business.