If you only need the building blocks to be available to docs from this template, then the simplest thing is to save the building blocks in the template. Since you already have the template made, and already have the building block made, you can open the template, then go to the Building blocks Organizer, and edit the properties of the building block so it is saved in your template.

You might have to edit the macro now that the building block is moved. I don't know.