You are starting to need more and more advanced features which Vinoma was not designed for and will require scripting, C# of Blox for example.
What you want to do can be done with a script. You could add the function in the same script used for the other functions, like the MyFunctions script I've shown before.
Since this script is already on an object,
_CustomScripts_, you can simply drag-drop that object into the area "show & hide object". Now you will find your MyFunctions script's functions in the drop-down you marked with "Show Object".
Simply add function like this to MyFunctions script and you should be able to select it.
public void ShowObject(GameObject obj)
public void HideObject(GameObject obj)