How to put the settings of one config file to other web config file?

<?xml version="1.0"?>
<configuration xmlns="http://schemas.microsoft.com/.NetConfiguration/v2.0">
    <connectionStrings>
        <add name="ConnectionString" connectionString="Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\Database.mdf;Integrated Security=True;User Instance=True" providerName="System.Data.SqlClient"/>
    </connectionStrings>
    <system.web>
        <authorization>
            <allow users="?"/>
            <allow roles="admin"/>
        </authorization>
        <roleManager enabled="true"/>
        <authentication mode="Forms"/>
        <!--
          Set compilation debug="true" to insert debugging
          symbols into the compiled page. Because this
          affects performance, set this value to true only
          during development.
    -->
        <compilation debug="true" targetFramework="4.0">
        </compilation>
        <pages controlRenderingCompatibilityVersion="3.5" clientIDMode="AutoID"/></system.web>
    <system.web>
        <anonymousIdentification enabled="true"/>
        <profile enabled="true">
            <properties>
                <add name="SCart" serializeAs="Binary" type="ShoppingCartExample.Cart" allowAnonymous="true"/>
            </properties>
        </profile>
    </system.web>
</configuration>

<?xml version="1.0"?>
<!--
  For more information on how to configure your ASP.NET application, please visit
  http://go.microsoft.com/fwlink/?LinkId=169433
  -->
<configuration>
    <connectionStrings>
        <add name="ApplicationServices" connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|\aspnetdb.mdf;User Instance=true" providerName="System.Data.SqlClient"/>
    </connectionStrings>
    <system.web>
        <compilation debug="true" targetFramework="4.0"/>
        <authentication mode="Forms">
            <forms loginUrl="~/Account/Login.aspx" timeout="2880"/>
        </authentication>
        <membership>
            <providers>
                <clear/>
                <add name="AspNetSqlMembershipProvider" type="System.Web.Security.SqlMembershipProvider" connectionStringName="ApplicationServices" enablePasswordRetrieval="false" enablePasswordReset="true" requiresQuestionAndAnswer="false" requiresUniqueEmail="false" maxInvalidPasswordAttempts="5" minRequiredPasswordLength="6" minRequiredNonalphanumericCharacters="0" passwordAttemptWindow="10" applicationName="/"/>
            </providers>
        </membership>
        <profile>
            <providers>
                <clear/>
                <add name="AspNetSqlProfileProvider" type="System.Web.Profile.SqlProfileProvider" connectionStringName="ApplicationServices" applicationName="/"/>
            </providers>
        </profile>
        <roleManager enabled="false">
            <providers>
                <clear/>
                <add name="AspNetSqlRoleProvider" type="System.Web.Security.SqlRoleProvider" connectionStringName="ApplicationServices" applicationName="/"/>
                <add name="AspNetWindowsTokenRoleProvider" type="System.Web.Security.WindowsTokenRoleProvider" applicationName="/"/>
            </providers>
        </roleManager>
    </system.web>
    <system.webServer>
        <modules runAllManagedModulesForAllRequests="true"/>
    </system.webServer>
</configuration>