How to dynamically select Web Config at run time

Dim a As String = Request.Url.Host.ToString()
        If Request.Url.Host.Contains("tes1.com") Then

            Try
                Me.MasterPageFile = "~/TestLogo1.master"

                ' Set the root path of the Web application that contains the
                ' Web.config file that you want to access.
                ' Get the configuration object to access the related Web.config file.


                Dim config As Configuration = WebConfigurationManager.OpenWebConfiguration("~/Web2.config")
                ' Get the object related to the <appsettings> section.
                Dim section As AppSettingsSection = DirectCast(config.GetSection("appSettings"), AppSettingsSection)

                ' Read the <appsettings> section.
                'StringBuilder appSettings = new StringBuilder();
                'appSettings.Append("WebConfig1");
                'appSettings.Append(section.Settings["WebConfig1"].ToString());
                Dim SettingValue As String = section.Settings("WebConfig2").Value

                ' Display the <appsettings> information.
                'ConfigId.Text = appSettings.ToString();
                Response.Write(SettingValue)
            Catch ex As Exception
                Response.Write(ex)
            End Try</appsettings></appsettings></appsettings>