I have searched for now a while, but did not find the right description for realizing a very difficult Multicompany-Structure (from a Holding down with different, mostly independent business fields, which have mostly independent companies, in different countries.....). Each of the companies should have its own accounting & financing, but they all need to have the possibility to work & communicate with each other (some times they have same customers and/or suppliers, as well as same peoples, which have different functions in more than one company - across the mentioned business fields or countries).

My main questions are:

A. How to set individual Websites (other Domains, Themes, Business-Addresses, ....) for each company?

B. On which level (Odoo-Database or Domain-Name) the handle of SSL-certificates will work?