<%@ Page Language="c#" %>

<script runat="server">

public void Page_Load(object sender, EventArgs e)

{

if (HttpUtility.HtmlEncode(Request.ServerVariables["HTTP_ACCEPT_LANGUAGE"]) == HttpUtility.HtmlEncode ("pl-PL"))

{Response.Redirect ("pl/");}

else {Response.Redirect ("en/");}

}

</script>

HttpRequest Request = HttpContext.Current.Request;       

     if (Request.UserLanguages == null)
            return;

    string Lang = Request.UserLanguages[0];

Now you have the browser language on behalf of that you can redirect to particular site.

if(lang=="A")
Response.Redirect("A site")
else
Respose.Redirect("B site");