I think you will have a problem with using the visibility options to achieve what it is you’re trying to do. This is because toggle visibility is what it says on the can - its a sort of on/off switch that can display or hide content, depending upon the initial state of what is displayed. In other words, it only has two states. What you’re trying to achieve requires three states. display the first content, hide the second content and replace the content with either the first or second content, depending on what is displayed at the time. This cannot be done with the standard on/of feature of toggle visibility. Instead, you will have to resort to a coded solution such as recommended by @Malachiman.
The use of such features must really have a “user intent” behind the interface logic. If we knew what the intent was, we could perhaps offer a more relevant solution for you. From what I understand at the moment, you need to have nothing displayed accept the two buttons and clicking one button will reveal 1 piece of content, and clicking the second button will replace that content with a different piece of content. This is relatively easy to do, but there is nothing to stop a user from clicking both buttons, which will result in both pieces of content displaying at the same time.
If you use visibility options, the best you can achieve is with a single button that switches content one from visible to invisible and, at the same time, makes content two visible. Clicking the toggle again would reverse the process, but this requires that there is some default content to start with so that the toggle can switch back and forth (the two states).
If you can tell us more exactly what it is you want to achieve and some explanation of the user logic behind the requirement, we may be able to offer a different solution.