Reply to Map buttons to specific effect levels?

Im relatively new to the mapping stuff, and Im a little stuck. Any assistance, would be appreciated. Im sure someone has done a similar thread to this, but in doing some digging on here, I couldn't find a specific answer to this..

What I am looking to do is assign a set of 4 buttons on an APC 40 to turn on, and essentially "jump" to a set percentage of the effect. This would look like..

Button 1 turns on effect A, and puts it at 25%

Button 2 turns (or leaves) on effect A, but to 50%

Button 3, same, but to 75%

Button 4, same, but to 100%

Hit any currently engaged level button again, and it toggles the effect off all together(and possibly have it reset to 0% as well).

Thanks,

Eric