Some of the websites (CHESS, E3S, Embedded, iCyPhy, TerraSwarm, TRUST) have a database backend associated with them. Workgroups can be created on these sites via the "Options" link.

Other sites, such as cps-forces, hi-cons, ptolemy and others do not have a database behind them. To create a group alias on sites that don't have a database, follow the instructions in Individual Mail Alias and when editing /etc/mail/aliases, instead of:

joyuen_e3s:                  joyuen@eecs.berkeley.edu

do something like:
execboard_cpsforces:         larry@eecs.berkeley.edu, sastry@eecs.berkeley.edu
Note that you will have to edit /etc/mail/virtusertable and run the commands at the top of /etc/mail/virtusertable to tell sendmail about the changes.

Also, you may want to temporarily set up the alias to point to your email address until you are sure it is working.