how do i create a group on linux?

You don't. Given your other stupid questions, you don't have any business trying to solve a legitimate problem on Linux. I think you should be beaten and Tasered for threatening to strap a rocket to a squirrel, for example.

A group of what? If you get 3 machines running Linux and put them together: Is that the sort of group you want?

Or are you talking about a group of accounts? To do what with them?

http://www.computerhope.com/unix/groupadd.htm