Grouping hosts in SSH Config

You should take a look at man 5 ssh_config for all the details on this, but yes, you can do that by doing this in your ~/ssh_config:

Host srv1 srv2 srv3
    User jorn

Host srv4 srv5 srv6
    User jornv

Host *.company.com
    User jornw

The * can also be used to do string matching for hosts