Arduino 5 Button Project

I want to have an Arduino take 4 buttons and ground 4 separate pads (each button will ground a different pad), however the 5th button will act as a switch when HELD. When you hold the 5th button the 4 buttons so ground 4 different separate pads (again each button will ground a different pad). Here is a quick video explaining what it is this project is for.

https://www.youtube.com/watch?v=LqOamj2wkyI