Experimente esta pequena função definida pelo usuário:
Public Function PeopleKounter(s As String) As Long
Dim DQ As String, c As Collection
Set c = New Collection
DQ = Chr(34)
ary = Split(Replace(s, DQ, ""), ",")
On Error Resume Next
For Each a In ary
c.Add a, CStr(a)
Next a
On Error GoTo 0
PeopleKounter = c.Count
End Function