Welcome Patrick. I am a member of the Tessier Family Association, and I can tell you that it is all inclusive. All of the Tessier lines are welcome and many of them are well documented by different members. If you do choose to join you will find that the Board of Directors and the membership are a friendy bunch, and will help you as much as possible.
For assistance in tracing your ancesters you should post another message to this forum giving as much detail as you can: the names of your parents and grandparents and their forebears if possible; dates of their marriages; ages; brothers and sisters names; where they lived; etc.