Add a new part-specific text style not propagating to full score

Sometimes it is useful to be able to add some text to a specific part without letting it propagate to the general score. One trivial example is the word "Tacet" used when in a movement of a larger work an instrument doesn't play at all. Another is when one wants to include some technical directions or pieces of advice, such as fingering, breath marks and the like, which would appear too verbose in the general score, where in addition space is at a premium.
It would be nice to have, besides staff and system text, a part-specific text style not propagating back to the score to fulfill this need.