Question regarding multisite with shared db

Dear,
I would like to create something and need help with what is possibly the best way to accomplish it.

1. I would like to have one site which is like big site where all advertisers are, like big engine where each of them is. Like aggregator.
2. Each advertiser can have their own site (so not just page on my supersite , but their own site either via subdomain or via add-on domain in cpanel but separated files and some part of database) and some parts of databases are synced with supersite while some parts arent. Example: add new product in woocommerce adds product in supersite and in their own site.

What is the best way to accomplish this ?

Kind Regards,
Ilija