User/Group Overview
You get to the User and Group Overview via the menu User in the menu bar (only when you are logged on to WebGenesis). The overview is arranged hierarchically and each group is listed in alphabetical order. All groups, to which you belong, and their members are shown:

The address information is shown when clicking on a user name:

When you select the link of an e-mail address (or "[...]" for groups) you can send a mail to a single user or a whole group (including the subordinate groups).
Note:
For this you need to configure an Email-Client in your browser; depending
on which mail program you use, you may have problems in using this
functionality.