Keyboard Shortcut for Custom Symbol

Is there a way to bind an unused command to a custom symbol, or remap an existing command to a new function?
I'm arranging a piano piece for classical guitar and want to distinguish between phrase markings and slurs, so I'm making slurs dashed instead of continuous. However, this requires a) selecting every slur after it has been placed and checking the dashed box, or b) clicking the dashed slur symbol I've created and put into a palette for every note I want slurred. Both of these are fairly tedious, and being able to, for example, change S from creating a default slur to creating a dashed slur would be wonderful.