Migrate a foreign Domino Server (domain) to our own Server

Hi, we have a new branch with a own Domino Server and a own domain.

Now, i need to migrate this foreign domain (domain2 + server2) to our existing domain (domain1 + server1).

A trust between this 2 servers/domains are allready there.

How can i merge this 2 server to finally domain1 and a single adressbook of server1?

Is there any tutorials or whitepapers?

Thanks in advance for any help

Volkan