I would like to know if in Odoo 9.0 there is a way to link one of system users (that could be people working in my company) and a specific vendor; I also would like to know if, with this link, I can obtain a mail sending each time a reordering rules is run to create a purchase order related to that vendor.

I know that each user could follow something, but I don't know if the following is about the reordering rules and if it could be useful to send mail to who are following.

Thanks