I'm looking to make a "dynamic" block for insertion into a drawing environment.

I'm looking to make a "dynamic" block for insertion into a drawing environment. This block would consist of an editable text note which would "ideally" stay centered inside of a polygon shape (to be determined). At one of the vertices of the polygon, I'd like to attach a leader with an insertion point at the end. This way, when I insert the block, I can change the "tag" letter, and rotate the polygon and leader around the note to a specified degree. Does anyone have a similar block or know how I would go about creating one? See picture for example. Thank you in advance.

SolidworksDrawings And Detailing