Destination based port forwarding
i want my pfSense home router to route packets with the destination mail.myhome.dyndns.tld:443 to server1:443 and if the destination is another domain the packets should be forwarded to server2:443. I only got one external IP where all packets for myhome.dyndns.tld arrive. Is this possible?
No, your router does not see the DNS query so it has no idea which hostname was accessed.
With HTTP you can pull some of that off with a reverse proxy, but I don't think the same thing works with SSL (I may be wrong, I don't work much with hosting SSL-enabled web sites)