How to send data to a particular Client from server in vb?

Question

I Have programmed a chat application in vb but as soon i send any data from client the server will send to all I should overcome this It should send reply only to particular client. This is the function i have used.

 Dim objClient As Client
        Dim d As DictionaryEntry
        For Each d In mcolClients
            objClient = d.Value
            objClient.Send(Data & vbLf)
        Next

where mcol clients is a hash table