Update: this question, including the title, was rephrased, see history for details
I know that the following App.config includes a external file:
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<appSettings configSource="appSettings.config"/>
<system.net>
<connectionManagement>
<add address="*" maxconnection="50"/>
</connectionManagement>
</system.net>
</configuration>
But I don't know how to move the system.net to the second file. Actually I haven't tried it, but I am almost certain that it will not work, and I want to know if there is an way for an App.config to include another App.config file by reference.