You will need to use Element Generator, as explained in the article here.
When you edit the element and add the shortcode from our plugin there, then click here to add some other fusion builder element:
And then you will have a mixed code like this (of course, you can also do changes manually to this code):
[fusion_code]restricted code block[/fusion_code]
It's not possible to do that between the blocks, so, for example, add opening shortcode in one block and closing in the other. This will not work. But you can insert elements into one block and that will work.