Autoassign shoppergroup depending of the landing page

[DaggaTora]

Hi,

I've seen many post regarding about how to autoassign users to different shoppergroups depending of a selection during the registration process.

My idea is to autoassign users to different shoppergroups depending of the page of the site where they register. I mean, I would like to have a couple of landing pages with registration form for users that come from ads in facebook and adwords so they will have a discount only for them.

any idea of how to manage this?