Local delivery and relaying

[Jan Ceuleers]

Hi

I'm a new Postfix user, having just switched from sendmail (which I set
up years ago and then forgot how).

I want my Postfix server to locally deliver emails for my own accounts
and those of my housemates, but relay all others. So for example:

Locally deliver these:
        us...@example1.net
        us...@example1.net
        us...@example2.net
        us...@example3.net

But relay all other destinations to the smart host.

I'm currently using the virtual_alias_domains feature, but this tries to
locally deliver all accounts within example1.net, example2.net and
example3.net. What I want is local delivery only of the accounts listed
in the virtual_alias_maps file, and relaying of all other destinations,
regardless of whether their domain.

I've done a lot of googling but could not find the answer (probably
because I don't know what search terms to use).

Any hints would be gratefully received.

Thanks, Jan