Here's a method that uses a relative path to open a VI reference. The VI reference allows you to manipulate the other VI at run-time. You can execute either VI, but because there is absolutely no communication between the VIs, they don't know which one started first, so both will be visible initially. As soon as you click the switch button, one will hide and the other will stay visible.
This is just an example to illustrate the concept for you, you should not just plunk this down into your project and expect things to work spiffy. If you have questions about this method, fire away.