Usando o VB.NET, como você converte o sid em Nome do Grupo com o Active Director

exemplo: preciso obter "group_test" e não "S-1-5-32-544"

O código que estou usando é:

Public ReadOnly Property Groups As IdentityReferenceCollection
    Get

        Dim irc As IdentityReferenceCollection
        Dim ir As IdentityReference
        irc = WindowsIdentity.GetCurrent().Groups
        Dim strGroupName As String

        For Each ir In irc
            Dim mktGroup As IdentityReference = ir.Translate(GetType(NTAccount))
            MsgBox(mktGroup.Value)
            Debug.WriteLine(mktGroup.Value)
            strGroupName = mktGroup.Value.ToString

        Next

        Return irc

    End Get
End Property

ou algo parecido com isto

        currentUser = WindowsIdentity.GetCurrent()

        For Each refGroup As IdentityReference In currentUser.Groups

            Dim acc As NTAccount = TryCast(refGroup.Translate(GetType(NTAccount)), NTAccount)
            If AdminGroupName = acc.Value Then
                ret = "999"
            End If
            If UsersGroupName = acc.Value Then
                ret = "1"
            End If

como você adaptaria esse código? (se o usuário estiver no grupo xx, mostre o grupo xx na lista suspensa)

        For Each UserGroup In WindowsIdentity.GetCurrent().Groups
            If mktGroup.Value = "BIG" Then
                Dim Company = ac1.Cast(Of MarketingCompany).Where(Function(ac) ac.MarketingCompanyShort = "BIG").FirstOrDefault
                If Company IsNot Nothing Then
                    marketingCo.Items.Add(String.Format("{0} | {1}", Company.MarketingCompanyShort, Company.MarketingCompanyName))
                End If
            End If
        Next