How to send emails to a mailing_list?

[carlobeltrame]

I want to test the email routing logic in mailing lists (Abos). To do that, I define a mailing list with an address. When using hitobito-docker, the domain I am forced to use is localhost, i.e. some-recipient@localhost.
I would then like to send an arbitrary email to the mailing list and observe the resulting outgoing mail in MailCatcher. Is that possible with this dockerized approach?