accept mail for other domain and forward them

Hello

I plan the following setup:

mx record:
10 sv1.domain.com
50 sv2.domain2.com

sv1:
- accept all mails for domain.com under normal circumstance

sv2:
- accept mails for domain2.com under normal circumstance (works
perfect)
- forward mails for domain.com from the local site to sv1 if they
arrives (works perfect)
- should accept mails for domain.com if sv1 is not running (as a
backup)

On sv2 runs also cyrus imapd for domain2.com. It runs perfect too.

How I have to config sendmail on sv2 to accept mails for domain.com and
forward them to sv1?

/etc/mail/local-host-names:
domain2.com
domain.com

/etc/mail/access
@domain.com RELAY

/etc/mail/mailertable
domain.com esmtp:mailus


Any hints are welcome.

Kind regards,
Martin