I'm afraid I have ask this question before but the answer was not quite fully sufficient... I've set a Workgroup for our company for staff only and now I've setup a computers service which provide internet for Clients which basically they are freely to use anything in that computer from Office to Games, Multimedia to Internet... but the question is how do I prevents those Clients computer from accessing our Computer Staff? the reason is because both Computers Staff and Clients Computer are sharing the same Internet Service Provider and in the same Workgroup. I tried using different Workgroup name (eg: SaffWorkgroup and ClientWorkgroup) but to no avail, people still can access share folder from each other and vice versa... Is there a complete secure way to set an entire different WORKGROUP at the same time sharing the same ISP? eg: Workgroup 1 cannot talk to Workgroup 2 but both can access the same Internet.