This came in to our helpdesk today, and then to my group (sysamdins), and I wasn't sure if this was a known issue or not. To wit:
When attempting to send an instant message to a group of individuals, there is no option through the GUI to send an instant message to any group. The options available are: "Rename Group", "Delete Group", and "Create New Group".
Cannot double click on the group's title to start a group instant message or through the "Contact" menu option. The option to send an IM to the group is greyed out and disabled.
When starting an IM with one person and then dragging the other members of the group manually into the previous two-user conversation, the group IM is then able to be sent. When this window is closed, the process must be repeated to send another group IM.
This same group IM functionality is able to be double-clicked on to send a group IM via Windows machines.
Tested on multiple 10.8.x and 10.6.8 Apple/Mac computers.
Q: known issue? Our Lync servers are humming along without any issues, so I'm thinking this is an issue with the mac client. ahhhhh, the great divide!