Send Text to Multiple Contacts
To send a text to multiple Outlook or Active Directory contacts in the Office 365 tab, press the Ctrl key on your keyboard and use your mouse to select each contact until all the contacts you want are highlighted.
Right-click on any one of the highlighted contacts to display the Action menu.
Select the menu option Chatabox Message to send a text to all the selected contacts.
The messages tab will be displayed and contain the conversation for that group of contacts.