Drop-down list in the content

Hello, after two hours of searching some sort of a plugin to help me achieve what I want, I decided to look for help here.

So here is what I have in the content of a page:

Clasa a-IX-a A

[wcs classroom="IX A"]

Clasa a-IX-a B

[wcs classroom="IX B"]

Clasa a XII-a A

[wcs classroom="XII A"]

Now, what I’m trying to achieve is to have a drop-down list at the top of the page, from where I can select which classroom* to be shown (in the same page).

*This means a classroom:

Clasa a XII-a A

[wcs classroom="XII A"]

The Flexible theme shares this idea. The only thing is that I would have to show only one thing for each option in the drop-down (Flexible doesn’t have a drop-down, but still, pretty much the same thing)