I have designed a website that accepts re-sellers and actually the concept of this website is having local re-sellers for each province (or should we say branches).

I have designed this website in a way that anybody who has a domain, can point to our website (a record or cname). well most of the website content are the same, the only difference is that re-sellers website doesn't have some items on the main menu and may have some small descriptions of their own branch in some pages.

I read that Google may ban websites with duplicate content (or which are significantly similar). I want to know will this be a problem for me?

If yes, what else can I do? we have had considered asking our reseller to use iframe that loads our website but wanted that each reseller can have its own SEO and try harder but what I read about this duplicate thing worries me.