For more information on using this script, see the article Adminstratively Managing User Contact Lists by Nick Smith.
# Contributed by Nick Smith, Microsoft
# Supported Versions: Office Communications Server 2007 R2
#Get User Information
$User = Get-WmiObject -Query "Select * from MSFT_SIPESUserSetting where PrimaryURI = 'sip: user@domain.com '"
#Get the contact group on the user's contact list
$ContactGroup = ( Get-WmiObject -Query "Select * from MSFT_SIPESUserContactGroupData where UserInstanceID = '$UserInstanceID'" | Where { $_ .Name -like " NAME OF GROUP HERE " })
#Delete the group
$ContactGroup .Delete()
