At first you need the group for sanity and survival.  But it's more than just the 12-step group meeting which you need, you also need your sponsor, your counselor, your daily quiet time, the phone calls, working your steps, staying connected to a local church, doing your reading, and staying connected to God.  But the group is a visible reminder of your recovery process.

After a few months the group will take on the role of helping you to maintain your sexual sobriety.  Now the group valididates your sobriety.  Your attendance is a witness to the fact that you are having continual victory over lust and sexual acting out.  The group becomes your cheerleader at you get month after months of sexual sobriety.  They will applaud you when you get your 30 day, 60 day, 90 day, six month, and one-year sobriety chip.

Later I hope the group will become before you a part of your ministry to help other people who are sexually addicted.  As the months go by your role in the group will change.  At first, you will feel as if you have fallen over the edge of a cliff.  But your are hanging tour branch on for desperate life.  Your sobriety at first is a cliff hanging moment by moment experience.

But after you have stabilized you will start to reach out to help others in the group.  You will start sponsoring other people, helping them to become successful in their victory over lust and sexual addiction.

So the answer to the original questioned is, "No, you will not need the group as you need it now, but you probably will stay connected as a witness and as a ministry.