Quiz creation help

Basically I am working on a language application and this is the outcome I want: -user sees a picture of an animal -selects one of four different buttons to test for the correct answer -if correct...then a new picture swings in and new buttons swing in and we repeat

HERE is my question... The picture switch is pretty easy .... but I realize ( now that I have assigned actions and sounds to the first set of buttons ) that I cannot stack more options on top of these because they would be accessible from the very first slide...

I either need to bring in 4 buttons for one slide and then take them out and bring in a whole different 4 (which sounds SUPER wrong!) OR find a way to mask previous actions while going through the interface...

I hope I explained things well enough

THANK YOU SO MUCH!