Email aliases different domains

[Grts]

Hi,

As email aliases now only support its own domain - is there a workaround so that I can send emails from the alias without logging in to the separate account?

Alias@domain2.com forwards to main@domain1.com but in order to send emails from the alias I have to login to that mailbox(?).

Before I could set aliases from whatever domain I had on the panel and was able to choose the from address on new emails but that was removed some updates ago.