[Samba] Multiple domain and trust relationship

[Julien Deloubes]

Hello guys,
i use Samba 4 AD  (4.2.1) for a small company.
I use a domain which is a subdomain of our internal DNS domain (
directory.mydomain.io)
Now my company will open several sites in different countries.
I was wondering what is the actual limitations of Samba4 concerning the
multi domain (i'm not a Windows guy and have very limited knowledge about
AD).
I read about trust relationship limitations (can be trusted but cannot
trust) so does this mean that for the moment i'm stuck with one domain?

What is my option considering multisites, could i continue to use only one
domain (with RODC for example)?

Thanks