Team Contests

Can users of one team log in 3 systems and submit solutions from different IP addresses. If it is possible which of the submissions are considered, if all the team members submit the solution to a problem?

No. I don’t think codechef allows multiple logins for a team event simultaneously.

You have to login with your team credentials, and only one session is allowed per team. To clear your doubts as there is a common handle so it doesn’t matters who submits the solution, when you logged in from another system your previous session automatically gets destroyed and you can submit from the new one and you can do this as many times you want, so login can be rotated between team members.For more info visit this.

No,users of one team cannot login at different IP addresses. If you try then a message to disconnect one of the login connections pops up.
But there is a easy solution, team members can still see the questions and can login only at the time of submission of the problem and logout after submitting. With coordination and logging in one by one only to submit solution can work.