Why do you need macro?
Can you select the area on the drawing and press "Delete" button? will it help?
Or do you want to delete notes in the same area for each drawing (macro will get the coordinates of the area from user and it will be the same for each drawing)?
Yes, there is a way you can do so. Check IDrawingDoc, INote and IselectionManager interfaces, and i think going through them will give you intitial push...