local mail only

Hi, everyone!

Please tell me how to make local_only mail environment with multiple domain.

I used it as a reference below.

https://community.zextras.com/restrict-carbonio-community-edition-users-to-send-emails-locally-or-externally-carbonio-ce/

But in case of 2 domains,

Each domain want to communicate with each domain's e-mail.

The article above shows single domain environment.

I tried to edit 'restricted_senders/local_domains'.

restricted_senders....user1@domain.A/user2@domain.B

local_domains.......domain.A     OK/domain.B       OK

I know this is wrong, because domainA can communicate with domainB.

If such a settings,

Actually, local_domain user's mail sent to spam folder mutually in spite of the same organization.

Please anyone tell me appropriate editing.

Sincerely.