There isn't. When you exit the vWii to the Wii U, the system is really just resetting. So the best option you have to accomplish what you're looking for is setting up CBHC to function similar to how you desire.
With CBHC, you can set your Wii U to automatically enter the Homebrew Launcher everytime the Wii U is turned on or reset. This would ensure that every time you leave the vWii, you'll return to the Wii U homebrew launcher, but this will also apply every single time you just turn your Wii U on. If you want to still default to the Wii U menu, but to go to the homebrew launcher on specific boots/reboots, you can use CBHC's shortcut to launch into the homebrew launcher by holding a specific button on boot (I believe it's B) when you see the CBHC load screen first pop up. You do have to hold a button this way, but it can accomplish what you want only when you specifically want to this way.