There should be an option to select the network connection for each application that connect to the internet. a lot of pcs are coming out with more than one built in network card and that is including wireless. an example would be i have my router setup with a vlan built in vpn and would like 1 application to be on that vlan. without having to have a separate application (vpn application/split tunneling) on my system to force the app to use that application.
this should be done very similar to how users can select what graphics card they want the application to start with in kde. aka right click on app, edit application, advanced, run using dedicated graphics card. so for the network it should be; right click on app, edit application, advanced, select network connection(drop down list listing default and options).
also in the network wifi and internet option, in system settings, when clicking on the network there should be a tab labeled programs and a list to add and remove (remove will set back to default). if default is selected on the app it does not need to show on the list. only those that have been changed. for a cleaner experience. but in the general tab there should be a option to select as default also default priority. example is i want wired first but leave docking station and switch to wireless. since those 2 are my default connection.