You can increase the amount of mail you send by specifying multiple server names in the SERVER attribute of ActivMail.
Each server does NOT need to be its own physical server, you can setup multiple virtual servers (see links below to see how to do this with Microsoft IIS SMTP server).
When you specify multiple servers in the SERVER attribute of ActivMail you are creating a thread for each server, this increases throughput, even if you have multiple threads sending to the same server.
If you don't want to add more physical servers, or virtual SMTP servers you can create aliases to your IP address. On windows edit your hosts file c:winntsystem32driversetchosts and add aliases. On unix edit /etc/hosts
Links