[O] Visibility cycling for headlines with a specific tag ?

[Martin Leduc]

Hi,
  I am currently taking a lot of notes in an org file containing figures, equations, code snippets and text. In my project tree, I have several nodes containing supplementary material and code that will not be part of my final report exported as a LaTeX pdf. These nodes are tagged as :noexport to avoid exporting.

However, when editing the buffer, I would like to hide all such parts in order to focus on the important ones. Is there a way to whether:
1) folding (or cycling) all headlines of a specific tag in one key action
2) prevent these tagged headlines to unfold (unless I specifically want to by hitting tab when the cursor is on the headline), by some kind of locking process ? For example, by tagging with :locked ?

Thanks for suggestions,
Martin