We have 2 domains (for example domain-a.nl and domain-b.nl). For Both domains
the e-mail will collected in domain-a.nl
For example my e-mails are and

My question:
Will it be possible to send e-mails easily from and another
e-mail from . Username and password is the same (same
IMAP-folder).

Now we use Tunderbird, in this program I easily can change the sender
e-mailaddress (with a pop-down)

I found 1 sollution, but this solution is not very handy.
I make that account 2 times. 1 with e-mailaddress and 1
with e-mailaddress
But now I see 2 times all my e-mails in the e-mail folder list.