Excel VBA - Sending Group Message via Lync / Communicator API

I am trying to send a group message to more than one user over Lync/Microsoft Communicator from Excel using VBA.

The below code works for a single e-mail address/user but if a cell range of two e-mail addresses is provided, it gives "Method 'CreateGroup' of Object IMessengerAdvanced' failed" error. Any advice would be greatly appreciated.

Sub sendIM()
 Dim msgr As CommunicatorAPI.IMessengerConversationWndAdvanced
 Dim msgTo As Variant
 msgTo = Sheets("Sheet1").Range("A1:A2").Value
 msgr = Messenger.InstantMessage(msgTo)
 msgr.SendText ("Test")
End Sub

The InstantMessage(Object) method supposedly works for >1 user according to this previous topic below, but in practice it doesn't seem to...

Lync notification of offline people using VBA

The interface expects an Array of email addresses when sending to a group.

instead of:

Sub sendIM()
 Dim msgr As CommunicatorAPI.IMessengerConversationWndAdvanced
 Dim msgTo As Variant
 msgTo = Sheets("Sheet1").Range("A1:A2").Value
 msgr = Messenger.InstantMessage(msgTo)
 msgr.SendText ("Test")
End Sub

test this:

Sub sendIM()
 Dim msgr As CommunicatorAPI.IMessengerConversationWndAdvanced

 Dim msgTo() As Variant
 ReDim msgTo(0 To 0)                       'Allocate first element
 For Each cell In Sheets("Sheet1").Range("A1:A2")'put your range here
     msgTo(UBound(msgTo)) = cell.Value2          'Assign the array element
     ReDim Preserve msgTo(UBound(msgTo) + 1) 'Allocate next element
 Next
 ReDim Preserve msgTo(LBound(msgTo) To UBound(msgTo) - 1)  'Deallocate the last, unused element

 'sometimes you need to use Set, sometimes you dont, depending on environment you have, or maybe OPTION EXPLICIT
 Set msgr = Messenger.InstantMessage(msgTo)
 'msgr = Messenger.InstantMessage(msgTo)
 msgr.SendText ("Test")
End Sub