Hide voicemail accounts from Lync address book

Hi,

We have a few response groups with voicemail accounts attached, the response group and voicemail have similar names which leads to people ringing the voicemail directly rather than the group.  Is there a way to hide the voicemail accounts from the Lync address book and leave them in the Exchange address book?

I've tried ABSConfig but can't see the attribute i add on the object in ADSIEdit.

Thanks