Customer Profile Provider using Multiple SQL Tables

I am trying to create a custom profile provider using multiple sql tables.
1. I currently have 3 groups in my profiles (Customer, Employee, Applicant)
2. Each group has separate tables for data. Do I need to write one (profile provider) for each group
3. As new users are created, do I use the profile provider to store the info, or can I just write the info to the tables, then use the profile select to read and use?
4. Anyone have any articles, and tutorials on creating a Custom Profile Provider using Tables that shows how to insert and update into each table?
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