The best way to ensure this happens is to include an assignment action in the process that is being initiated by the inbound email. You can then define the group and an analyst if necessary, but I wouldn't have anything assigned to SA. The call may have been created by SA, but it shoujdl be only assigned to real analysts and groups.
If you are using the common feature of a suggested initial assignment on the incident, then modify the template on your mail manager to use a template with the initial assignment set up to the group you want. That is a quick job. If you are not, consider implementing it as it is very handy!
Good call Dave!
This is another method of solving it, just depends on the design you want to implement.