You may communicate with any ONmail Business Class user via the ONmail application.

To add users to your Currently Online, choose them from any of your Contacts lists or groups.

1.) Click the Currently Online drop-down menu, and select Modify list.

2.) Your Contact lists will be displayed at the left.  Choose any user from any list or group, and they will be added to the Currently Online list.  To include all of the Enterprise Contacts in this list, check the box next to "Show all enterprise contacts in my currently online list".

3.) Click Save.