You can set up groups in the Groups section of the administrative interface.
To do this, select Groups on the left-hand menu. By default, there are pre-defined groups such as ''All office personnel''. You can create customized groups, to which you will then be able to send specific messages.
To create a new group, click on the name of the first person you would like to add, from the list. Hold down the Ctrl key on your keyboard, and click on each of the following people you want to add. Once you have highlighted all the appropriate members, type in the name of your new group on the right side of the page, under Add a group. Lastly, click Add this group to the list.
If you want to add someone to the group later on, you can return to this page and select the group under Customized groups. Hold down the Ctrl button on your keyboard, select the additional person from the list, and click on Save modification to selected group.
You can now send out group messages via the main send a message window.
When in the send a message window, you simply type "group" in the recipient field (the "to" field). You'll see all the groups in the office.
Select the group you want to send the message to. You will see your new group's name in the list. Write your message and click on send message now. All the members in the group will receive the message.