private void WcfCrmClientOnCrmServerCallHistoryEntryAdded(object sender, CallHistoryEntry callHistoryEntry)
        {
            lock (_lockObj)
            {
                var affectedEntries = _internalCrmEntries.Where(entry => entry.PhoneNumber.Equals(callHistoryEntry.Callee) || entry.PhoneNumber.Equals(callHistoryEntry.Caller));
                foreach (var affectedEntry in affectedEntries)
                {
                    affectedEntry.CallHistoryEntries.Add(callHistoryEntry);
                }
            }

            RaisePropertyChanged("CrmEntries");
        }