Hi Piyush,
it is possible, but you will have to make your users clear, that they definitly have to log out. If two users will work from the same computer, they have to do it after another and not to the same time. So if one user is finished he has to log out. If he doesn't do it, he will stay logged in until the cookie's time is up and the other user is logged in under the name of the former user. But if he logged out, any other user can log in and there is no problem. If you want to have definite scripting help feel free to ask me,
Andreas