Well, on a 3000, you can use the "Press" state of a button with variables, so you could just not have a press state, and make it dissapear that way. I'm not sure there's a way to make the button dissapear per se on a 950, but you could use variables to make every subsequent press after the initial not do anything.

Using the method described for the 3000, you could "Stack" 3 buttons, when you press one button have it switch It's own Variable to 1 (the invisible state) and set whatever button you want to replace it to to 0 state (Visible State). Hopefully that makes sense. (and works)