I have limited knowledge in UE4 this is the way I would do it. This might be not the most efficient way to do it, there might be other ways to solve it that is better than this.
I assume your button is only an actor in your level.
You make an array containing all your button reference. Arrangement in making the array is important.
After adding them to an array. Add this after your linetrace node.
Every time you click it will read your array and check all the buttons you placed there comparing it to the hit actor of the line trace, when the proper button was found it will continue to the switch on int.
0 is for the first item in the array, 1 is for the second, the rest follows.
For example button one will make something fly, you put the fly function on the 0 part of the switch on int. The second button will make something disappear, put the disappear function on the 1 part of the switch on int.
The default as the name implies the default function to be called when the integer range exceeds the declarations.
I reccommend you to make a blueprint that can be the parent of all your buttons and you can reduce that making of array to this. There arrangement would be the first blueprint you placed on the map will be the first item in the array.
