is their any way to secure two wrok groups without accesing each other and theirs no way to chang the ip address b caz all machines accessing internet using internet connection sharing through one machine the range of ip is 192.168.0.1 to 192.168.0.254 i ve tried changing access this computer from the networ option in security policy but it wasn't make any sens please help me to get rid from this caz i am tring for a one week

You need to be a little more clear about what you want to do. You want to prevent users from accessing other computers on the same network?

i want to prevent each workgroup members from accesing each other but internaly they should have access are u clear what i mean please

"prevent each workgroup members from accessing each other but internaly they should have access" ... to the Internet?

The purpose of a workgroup is to share information. What you are asking for is counter to that purpose. If you don't want the workgroup having access to other machines via the network or being able to just walk up and logon you would have to start by removing File and Print sharing. This will make it so the computer can not be accessed via the network. You would only have the user account on a machine they were to logon to and no other accounts. Only that person could logon locally. Both would defeat the purpose of a workgroup. Perhaps you may want to post what issue you are trying to address than asking for a solution.

how do i secure the 2 workgroup from where can i do this local policy